Why is there a diesel behind the steam engine?

It's often asked why there is a diesel locomotive behind the steam engine. And it's not necessarily 'because the steam engine isn't reliable!'
In this video, I'm going to explain some of the reasons why various steam locomotive operators may choose to run a diesel locomotive behind their steamer.
Royalty free music courtesy of www.bensound.com

[@gewoonwatfilmpjes]

Few reasons for the diesel behind 4014. It provides dynamic braking, saving brake shoes. It supplies pulling power to reduce fuel consumption on 4014, and it is the prefered force when driving through tunnels. Finally, it is used for communications and as a backup when 4014 has issues. This happened once when 4014 ran out of water.

[@MLIW265-FAN]

And also electricity for the passenger cars

[@paulblichmann2791]

Blah blah blah. How did they do it in the old days??? I want that or nothing at all.

[@southwestvirginiarailfan729]

@@MLIW265-FAN They have a generator car for that. Freight diesels don't have ability to do that.

[@xmodgaming5995]

@@southwestvirginiarailfan729 they don't have that the diesel electric engine built by emd does provide power as the locomotive is basically just a big generator that provides power for the electric traction motors.

[@Tchristman100]

@@MLIW265-FAN UP has a separate generator car-the one with a long roof bump.

[@Train115]

Modern coaches don't have dynamos anymore, often they are used to supply power to the cars. They also assist with braking.

[@JohnGeorgeBauerBuis]

Yes, dynamic brakes are one of the best railroad innovations ever created!

[@InventorZahran]

Freight diesels can't supply head-end power to the coaches, so a dedicated generator car (or a passenger diesel with HEP capability) is often required.

[@alexclement7221]

Some years ago, a Canadian railroad (CP, I think..) ran a special steam train from coast-to-coast. They also used a diesel as part of the consist, but what they used was a recently-overhauled EMD FB unit, set right behind the tender, painted to match. If you didn't know much about trains, you probably wouldn't have known there was a diesel there. I think railroads do this mostly because the steam locomotive is really an antique; these machines are 70+ years old, and parts supply is severely limited. Just 1 75 year old part breaks, and the whole thing stops. Also, infrastructure needed to service steam was dismantled more than 50 years ago. Just finding enough clean water to replenish a steam loco is difficult in dry areas. UP found this out when they hooked up the Big Boy to one small town's water system, and ran their water tower dry! They were asked to never stop there for water again...

[@litebulb2699]

So I wasn't going insane all those years ago! I was by the station when it stopped in my city--no one who wasn't there believed me when I said I smelled coal smoke and heard the whistle at the bus stop.

[@Aftermath779]

It's interesting that an EMD F Unit has modern fixtures for when 2816 is going to go out for it's tour.

[@justahillbilly7777]

Just a heads up on the 4014’s PTC system, the plan is to make the system completely standalone, and the same is true for the 844. I asked in the Union Pacific’s Steam Club bookFace group if that was still the overall plan and it was confirmed that it’s still the plan, and that 4014’s system has been made to be completely standalone now, with 844 to soon follow. Long story short, let’s not completely give up hope on a steam only run on Uncle Pete’s mainline with the Big Boy.

[@andrewdonohue1853]

She sure has the horsepower

[@justahillbilly7777]

@@andrewdonohue1853 And the tractive effort. If 3985 can handle a 143 car double stack intermodal at speed, I don’t doubt that 4014 could do the feat with a 200 car double stack intermodal. But with Ed having admitted in the Steam Club bookFace group to actively taking it easy on the engines for the sake of making sure they’re in the best possible condition for future generations to continue preserving and using them, in spite of his own admitted desire to see and operate the engines the way they were built to be, the prospects of seeing such a feat with the 4014 is iffy at the very best.

[@andrewdonohue1853]

@@justahillbilly7777 i think taking it easy most of the time is just fine, but once in a while we need a demonstration of the power of these incredible machines. a big boy is no toy..... makes me wonder if there's even a diesel that exists that can match it. i doubt it.

[@justahillbilly7777]

@@andrewdonohue1853 The EPA Tier 4 compliant SD70ACe’s and the DDA40X’s have more starting tractive effort then what the Big Boys have. But when it comes to being able to solo haul a single train, I’m unaware of a single diesel locomotive capable of giving the same performance of a Big Boy. Like the old saying goes when it comes to the raw power and power curves of the two types, a diesel locomotive can start a train that it can’t pull at track speed, whereas a steam locomotive can’t start a train that it can pull at track speed.

[@thomasmleahy6218]

@@andrewdonohue1853 Didn't the UP have some articulated diesels, real tall fellas? I saw some ungodly huge units at the Proviso diesel ramp back in the '70s-'80s. Should've shot a few photos, but didn't have my camera handy, and they were gone the next day.

[@ArizonaRails]

A question I'm glad was finally answered by someone who is experienced with these iconic beasts! Amazing video, Eric! -AZRails

[@rodneyrev]

Track operators requiring a diesel in the consist on buy lines is common everywhere and another reason is that older steam locos are unable to provide electric power to the consist. Here in Victoria (Australia) we have had triple header steam trains with a lot of cars and it is an awesome sight pulling up the hill in the dark near a friends place.

[@andrewdonohue1853]

did later steam locomotives have the ability to power a consist? did the steam generator ever provide that kind of power? wasnt it always a generator car, and cant that still be done to today? a generator car?

[@RodneyMarchant-bg4hq]

@@andrewdonohue1853 As diesel locos are actually hybrids, that is the diesel engine drives a generator which in turn powers electrical motors which drives the engine it should be obvious that the diesel loco is powering lighting and heating to the consist. Why would you have a generator car?

[@andrewdonohue1853]

@@RodneyMarchant-bg4hqi i was talking about steam operation in 2022, cant they have a generator car instead of a diesel locomotive?

[@RodneyMarchant-bg4hq]

@@andrewdonohue1853 Never heard of a generator car, has anyone else?

[@TheDemocrab]

@@RodneyMarchant-bg4hq Not every diesel has the ability to supply power to the train as it's not drawn off of the main generator as you're implying, instead a much smaller engine/generator combo supply what is called Head-End power to the carriages and sometimes even refrigerated freight. Here in Australia the A/B classes (Which ran some services until fairly recently) never had HEP and required a "Power van" which was essentially a engine/generator crammed into a boxcar to supply the HEP, you'd also often see them still attached to the carriages when hauled by a modern N class despite the N class having HEP as it meant that the carriages would still have power while the locos detached to run around at the terminuses of the line, plus it was a bit of redundancy: If either power source was broken then they could just use the other one.

[@mattmobes_1025]

The technology used on the Big Boy to tie PTC in to the diesel is called LeapTC, and was invented over here at 2926!

[@ehadder]

So 2926 will have to have a diesel in PTC territory?

[@mattmobes_1025]

@@ehadder For the foreseeable future, yes.

[@wolfgangwolfdogplaysguitar701]

2926 what year is that?

[@thunderjet4294]

@@wolfgangwolfdogplaysguitar701 it's not a year it's the Santa Fe northern 2926 belongs to the nmhslrs

[@mikemallano2484]

According to Ed Dicken's head of U.P. steam, the diesel provides head end electric power to the coaches, insurance in case of breakdowns, plus shunting service at night when the steam engine is shut down.

[@lordsherifftakari4127]

the most common reason for a Diesel to accompany any Steam Loco on excursion runs is today's Railway Dispatching system also uses in cab signaling which very few Steam Loco's have had added. the Diesel can talk to Trackside Devices and maintain contact with dispatch during the run while also supplying head end power for passenger equipment. though one alternative to the Diesel for this role would be to place the Cab Control system inside the leading coach or Baggage Car along with a stand alone Generator to create a Power Car for the train. but running on Revenue Rails may require the need to have one or more Diesels along as noted in the Video J.I.C. Steam Loco's like any other piece of large Mechanical Equipment can and occasionally DO break down or suffer some sort of Mechanical issue and need a "Tow" to the next siding to clear the main.

[@FarlandHowe]

I always wondered about the diesels behind the steam. I had assumed prior to this video it was there for electrical power to run the AC and lighting in the passenger cars. I was there when 4014 first came out of Cheyenne and stopped in Laramie, WY on the way to Promentory Point. That was when I first noticed the diesel. Certainly 4014 had plenty of tractive effort to pull about anything. Rob

[@lolroflpmsl]

I believe the same is done on steam railtours in the UK - HEP for coaching lights, heating, and A/C - and for backup traction. Most UK heritage steam is speed-limited to 75 mph, though the new build(s) (i.e. Tornado) can do 90 mph. A good chunk of our network is 110 or 125 mph.

[@volvomad]

Uk railtours have a diesel on the rear for those times the train is pulled backwards for example at a terminus station. Flying Scotsman is going to South Wales this year - it is turning on the triangle in Newport then being pulled backwards to Cardiff so it's facing the right direction to return to London. Most railtours have a diesel generator in one of the end coaches.

[@mikecross4350]

Most tracks are limited to 55

[@lolroflpmsl]

@@mikecross4350 in the US?

[@mikecross4350]

@@lolroflpmsl yes

[@henryostman5740]

I believe that the speed limit on a steam locomotive that has stood idle for over 60 years is just that, you could put a Eurostar locomotive on the front of it and it still couldn't be allowed to go faster. But all the other issues stand; dynamic braking, communications, head end power, tunnels, and turn-around issues.

[@dawor1761]

My thought is simple; it's to reduce the stress and wear on the old steam train. That Steam train engine is a valuable piece of Historical equipment. And It runs and works!!! Outstanding! Take good care of it.

[@BaloonLlama6056]

8:15 such a beautiful noise to hear

[@hawghead4596]

Back in 1998 I rode the Grand Canyon RR from Williams, Az to the South Rim, Grand Canyon. We stalled going up a hill, had to shove back and get another running start, after sanding the rail. There was no diesel helper then.

[@lowrangemaniac5326]

There in south Italy there's a narrow gauge railway, and on this railway they run a steam train for touristic rides... They use only the pure power of the steam locomotive, while the train is followed by a diesel engine attached to a water tank... This is a fire fighter train and is used to extinguish fires that may be caused by the steam train passing by

[@nicopavvi8494]

Is it the Calabro Lucana railway?

[@lowrangemaniac5326]

@@nicopavvi8494 exactly! They use the FCL 353 Borsig tank engine to do this touristic train every sunday, and on some special events, and it's followed by the FCL LM 004 to prevent fires along the tracks... Very recently they bough the twin of the FCL 353, the FCL 358, and bring it back in south Italy from Rome, and their plans are to functionally restore it, to make even more touristic steam trains

[@robertcervenka6875]

Sort of a hybrid system

[@robertcervenka6875]

Smart

[@lowrangemaniac5326]

@@robertcervenka6875 it's just a way to prevent fires in the wood, because the railway runs in a naturalistic park, and especially during summer time, you cab immagine how much dry grass there will be around the track... So, to prevent them, a diesel engine follow the steam train some 100 meters behind, while pulling a tank of water

[@starguard4122]

This was very informative. All this time I always thought that diesels were only added for dynamic braking

[@jked7463]

I have asked this question a few times and have got many,mostly silly reasons ( including the diesel engine is being pulled along as only an electric generator) so thank you for answering with real answers.

[@TheDemocrab]

The drivers for the former West Coast Railway in Victoria, Australia (Which ran mainline steam in the 90s/00s) outright said that diesel and steam locos compliment each other as well as toast and butter do.

[@richardburdick9430]

In June of 1998, Milwaukee 261 was running an excursion train to Galesburg Il. for the Galesburg RR days festival. East of Mendota, the locomotive developed a hot bearing, and tied up traffic for a while. I have never seen solo steam on the BNSF since (there may be an exception or two, if so I am unaware).

[@tpep1693]

I'll answer the question before I hear the answer, "Problem's can arise", plain and simple.

[@jm_trains]

I love how on the Reading and Northern they manage to operate excursion trains on 425 and 2102 without any diesel help. You see it more often with narrow gauge like Durango & Silverton or Cumbres & Toltec but much less common with large locomotives on the standard gauge.

[@coniow]

There is another point here: These locos are historical artefacts, are very valuable, and you don't want to wreck them just to prove what they CAN do when pushed to the limit. A diesel unit fails: Plenty of spares, and replacements. A Steam Loco brakes, you might have to specially cast a one-off piece, then machine it Etc, Etc. If it is too costly, you than have a static museum exhibit, not a running Loco. Historic WW2 'War Birds" are limited to how many flying hours they have in any given year, and prohibited from "Aerobatics" that would stress a very valuable, irreplaceable airframe to much.

[@DesertAdventuresinArizona]

We traveled to Benson Arizona in 2019 and watched 4014 stop there. It was amazing!

[@ehadder]

I was there as well. I have another video about chasing the 4014 from Tucson to Lordsburg.

[@buecomet831]

I just thought it looks cool to have a diesel behind a steam locomotive to me when I was young. Idk why but it was just cool to see a steam and diesel working together.

[@wolfgangwolfdogplaysguitar701]

But they don't get along very well

[@TheGenericavatar]

The Southern Pacific 4449 (4-8-4 train, called the Freedom Train in 1976) that was once a 'California Flyer' (I think it was). When we chased it in SoCal some decades ago, it had a diesel behind it. I later discovered that it was because at the time, the boiler was not certified for full, normal operating pressures. As such, it didn't have its full power available. Otherwise, the diesel was unneeded for what the train was pulling, even over the steep grades of El Cajon pass (Tejon? The one heading inland East from the coastal regioun of SoCal). If there were other reasons, I never heard them.

[@jamessimmons1888]

The Tennessee Valley Railway Museum runs excursion trains and they use both steam and diesel engines. They use the diesels for extra power up steep grades and also in case of mechanical problems on the steam engines.

[@elvinhaak]

I can also think that running a steam engine just for backup is pretty expensive this days. You still would need to bring it p to steam and keep it that way although not used at all while diesel can be started much faster. And also: these old diesels are beautiful too ;-)

[@jandoerlidoe3412]

Interesting video; I always thought the diesels where only as a backup in case the steam locomotive fails... but there is much more to it... providing electric power to operate modern day safety features, providing power to passenger cars, giving boost to start a heavy train, and when taking on gradients, and to help in maintaining high service speed required by modern track operations - when the excursion train has to fit in a track used by commercial train traffic . Especially the observation that a steam locomotive can pull any train it can start & that a diesel can start a train it cannot pull is eye opening,,,

[@JoshKilen]

very nice video, when the up 4014 came up to Duluth, Minnesota, they used the diesel to allow just the locomotive to come into the station by its self, tight curves at the Lake Superior Railroad Museum/North Shore Scenic Railroad. Btw I do have a video on my channel with it coming into Duluth.

[@randyr476]

Great video thank you. Big fan of the GC Ry, having ridden this summer with my oldest grandson. And just recently on the Polar Express with the local grandkids.

[@stlpaulie]

I seem to remember one time when the 3985 stopped in St. Louis they had trouble with the boiler and since they didn’t have the back up diesel it sat here for two or three days.

[@tcmw779]

While I love steam locomotives, I understand, that it may be A GOOD IDEA that a diesel-electric may be a good idea to have in the the consist, "just in case". IOW: stuff (can/will) happen!

[@jackfetters2504]

I was the conductor on that UP trip from Yermo to Vegas in 2000

[@InverhavonRailways]

In the UK the diesel is attached to the rear of the train, and is there to provide train power, and pull the whole train in reverse, avoiding running round.

[@volvomad]

At least one of the UK railtour companies has a generator in one of the coaches. They only tow a diesel when the train is expected to visit a terminus station

[@kiarash608]

At least some railways have the good will to attach them at the end of the train so they don't spoil the fun too much. Out of sight, out of mind

[@robertnorton3047]

I had the opportunity to talk to the passenger car foreman on a UP4014 tour. His explanation was it was primarily to power the passenger cars

[@uncinarynin]

The German term for this is "Angstlok". On some lines it's required, especially in tunnels that would get too sooty if steam trains ran under power in there.

[@kevanhubbard9673]

The diesel is there for emergency backup in case of breakdown plus it's probably supplying hotel power to the passenger carriages assuming that they don't have a generator carriage.

[@ffjsb]

When Norfolk Southern had it's steam program running in the 80's and 90's, they rarely ran with diesels. They had a Head End Power car (HEP) that supplied power, and many of the cars also had their own diesel generators underneath with the other appliances. The Ohio Central didn't have places to turn the steam locomotives like the NS did, so they ran steam in one direction, and had a diesel on the other end to run back on longer excursions.

[@timothykissinger4883]

Back in 1980,I took a trip on the Victorian steam locomotive. It did have a diesel locomotive behind the tender only for extra power going up hills.Other then that it ran on steam.

[@MagnetOnlyMotors]

I thought also it gave electricity to the pullmans.

[@SocialistDistancing]

If the diesel power blended in better, like a B unit, it wouldn't be as unattractive. Using it as switcher at a dead end has merit. Could there not be a switching unit stationed at the dead end?

[@jacksalvin364]

Well it's for dynamic brakes and steep grades to climb.

[@CJ-jo6do]

While I was visiting the 4014 during a stop in Jefferson City, Missouri, one of the crewman stated that one of the main driving reasons for the diesel is for the air compressor, the 4014's air compressor may have been good enough for 1950s railroading, but modern FRA standards require more air to recharge brakes. And like others have stated, having dynamic brakes, PTC, and diesel power to save fuel & slow wear & tear of a fresh complete overhaul'ed historic locomotive.

[@williamkurzenberger4607]

Some one should invent a powerful, dynamic-braking diesel unit that looks like a baggage car or box car. That would preserve the appearance of the consist. Maybe it's been done??

[@robertknight5024]

The diesel is there because it provides electricity for the passenger cars for lights, heating, cooking etc. Those steam engines had more than enough power and braking for the job, they just don't make electric. The other reason is the computer and radio systems for train tracking. From a retired railroader...

[@localenterprisebroadcastin5971]

I can think of a few reasons…1 reliability 2 lack of supporting infrastructure for steam power (IE fuel/water) 3 braking 4 assist with steep grades 5 alternate power for electrical systems and air.

[@TheDefiantPirate]

4960 on the Grand Canyon Railway uses the Diesel because it can not haul more than 3 or 4 of the main passenger cars the GCRY uses up the grades especially the 4% wye at the canyon

[@Big_Diehl]

Close, it’s limited to 7 cars.

[@rennethjarrett4580]

I figured it was due to the trains running on the main lines and if the steamer had trouble the diesel could move the train out of the way. On a steam excursion in the 1980's I recall there was a problem with the steamers on the main lines due to the lack of tracking boxes on each rail car, so in the future they would have to have upgraded rail cars boxes for tracking the train or else they could no longer run excursions.. Strasburg Rail Road running their little double header on the main lines from Strasburg, PA to Harrisburg, PA.

[@davebrown6598]

A very knowledgeable presentation!

[@michaelodonnell8209]

I understand you excellent explanation of why they generally run diesel units with steam, but I still prefer to see a stand alone stem locomotive chugging along without diesel, because I want to live in an untarnished past which has disappeared. I am no longer young, so I also miss seeing a caboose and waving to the man in that last car. When I see a train without a caboose, and cabooses are gone forever, I can't help but feel something is missing. You can't stop progress. Imagine a time when all the helper units at the end or the middle of a train were fully manned by separate crews. Technology replaced those people, just as technology eliminated the caboose.

[@byrd203]

The desiel is not for backup power I can confirm straight from ed dickens it is to prevent from wearing out the brake shoes and having dynamic breaking going down the hills as well the engine stays idle until then need to reduce the load going up hill but mostly used for breaking saving wear and tear on the steam engine because its hards as heck to change them out make them last as long as possible

[@thatcarguy1UZ]

Just a thought, I realize that while running on a busy Main Line you would want to have a diesel engine for backup power in case there was a propulsion failure with the steam locomotive, but for smaller trips on less busy lines, couldn't a car with a diesel generator and equipped with PTC equipment that looks more like a traditional steam era Railway coach be used to provide the 440 volt electrical power and the positive train control equipment that would interface with the steam locomotive and allow it to operate?

[@williamdixon1992]

That video answers some questions That I had as to why is there a diesel locimotive behind a steam engine? Thanks!

[@KnapfordMaster98]

unrelated but the 1522 is so beautiful, I wish there were enough opportunities to run it to justify a restoration.

[@teenytinybricks]

I believe there was one time 844 had a boiler issue and had to get towed back dead by 3985. With steam locomotives being especially prone to mechanical issues, it's good to have backup.

[@timesthree5757]

As apposed to diesel’s catching fire all the time.

[@megatop412]

That was fascinating, thank you

[@mr_mcgoo2632]

Main reason to provide electrical power , 2nd back up power if needed but normally the diesel is free wheeling

[@thegamingtako9779]

Also ( I haven’t watched the whole video yet so I apologize if this was mentioned) I believe they do it to provide electricity to the consist in case the dynamo on the steam locomotive failed for whatever reason or of the locomotive is old enough and wasn’t fitted with electrical hook ups for cars

[@TheKurtsPlaceChannel]

Very nicely put together video and very entertaining as well. Thanks for posting this.

[@HueyRailfanning]

On most occasions when I've seen steam engines (Sugar Express and GSMR), the diesel(s) were at the back of the train, and I'm quite sure it was just so the train could be turned around easily. But, I've also seen steam run on its own with no diesel whatsoever either. Didn't know there was this much reasoning to why they put diesels on too.

[@redmist5890]

Simple its for Justin

[@SteveS-dj4nq]

Regarding diesels on U.P. steam excursions I think they are only there for pulling and braking, but not for HEP. I doubt the various road diesels used have the necessary ports to plug passenger car standard power into. Also I believe the U.P. Passenger trains are self contained with generator cars in the consist supplying necessary power to the coaches.

[@freddykagin]

Thank you for sharing.

[@redlight722]

Senior manager-Union Pacific Heritage Operationsand Big Boy #4014 engineer told me, that it was there only to power the coaches. I met him in Little Rock shortly after he tied down for the evening.

[@ehadder]

I'm afraid that doesn't make much since, since UP uses freight diesels behind their steam locomotives. Freight diesels do not have the ability to provide Head End Power. I believe UP uses a generator car to power the coaches. You can see it in my video of the Big Boy runby. I think it's the car with the bubble on top, because it sounds like a generator running when it rolls by the camera.

[@redlight722]

@@ehadder Straight from the mans mouth. I have it in a clip my wife took of us. And what do you mean “freight diesels”? Does UP have passenger diesels hiding somewhere?

[@ehadder]

@@redlight722 A Modern Passenger diesel, like the ones owned by Amtrak or the commuter railroads, will have the ability to provide Head End Power for the passenger cars. This runs the air conditioning, heating, lights, etc.. This can be evidenced by large electrical cables that stretch from the diesel to the cars, and between each of the cars on the train. To my knowledge, UP does not have any of these, except perhaps the E units, but they have never run behind the Big Boy. Most Passenger diesels are going to provide the Head End Power in one of 2 ways: Either a separate electric generator connected to the crankshaft of the diesel engine, or a separate diesel engine with it's own electric generator. Electrical systems on Passenger cars run on 480V 3 phase at 60 Hertz. So the diesel engine needs to run at a specific RPM in order to provide the electricity at 60 Hz. The more modern Passenger diesels may have a way of taking part of the traction power and converting it to 480V 3 phase at 60 Hz. I'm not familiar with those.

[@henryostman5740]

It is probably unlikely that the steamer has modern in-cab radio and signaling devices and even it it did the diesel would provide redundancy, the diesel can use its dynamic braking to reduce friction braking by the locomotive saving brake pads and wheel tire wear and the diesel likely can provide hotel power to the passenger cars for lighting and air conditioning, I am sure the old steam powered A/C is long gone.

[@pupsmotorworks5228]

Nicely done, and explained.

[@TheRuffusMD]

the diesels , provides electrical power for Ac kitchens etc . plus the power for the air brakes . the below comments also list great reasons

[@HMSNeptun]

As impressive and powerful as steam engines are, the US should really start considering electrifying their railways, removing 'freight priority' and acquire modern EMUs for regional rail. and as cool as steam engines are, no steam engine is going to beat an EMU on acceleration, tractive effort, and reliability

[@TonVerkleijT3]

Resaons enough, but mostly diesels are added for mistrust towards the steam engine's reliability and of idiot safety rules. Steam engines in Europe and Asia run on their own, and museum steam engines in Germany, France, the Netherlands and the UK run full services on the main line on numerous occasions. No need for brake assistence or extra power, these engines are very well up to the job.

[@peteverhelst2088]

In Canada I understand steam is not allowed to run without diesel assist as explained in a video about the royal Hudson 2680

[@stevenlennaman2073]

I would have believed in supplying electricity to the passengers' cars. What we in the Navy would call Hotel services.

[@scenicdepictionsofchicagolife]

Another reason for the diesels, is for PTC and HEP (if pulling passenger coaches).

[@raylrodr]

So many experts and their speculations!

[@garyscott5746]

In the UK it's the norm to have a diesel with steam for a few reasons one in electrical supply to the coaches and the second is that the steam locomotives are old and may require assistance,. They also lend a hand should it need it

[@volvomad]

Normally only used when the train is expected to visit a terminus station to haul it back out. They use a generator in one of the coaches any other time. Look at steam railtours on KZbin for many examples of steam only trains

[@volvomad]

Also worth noting - although the steam locos are old, they are stripped down every 10 years for overhaul. This makes them run like new. Although failures do occur, it is very infrequent.

[@russvoight1167]

A good policy for alot of reasons, better to have it than need it

[@eliasthienpont6330]

The Reason for the diesel is to provide hotel power to the coaches. Once upon a time they were heated and even cooled by steam power. Electricity (36 v DC -- I think) was provided by batteries charged by a generator taking its power from one of the axles. Many older passenger diesels had steam generators to heat the coaches back in those days. Freight locomotives had no steam generator. Today's coaches are all heated and cooled by 480 volt AC power provided by the diesel locomotive. Only purpose built passenger locomotives can provide this power, most freight cannot do this. Older coaches have been converted to this standard otherwise AMTRAK will not certify the coach for connection to its trains. People who have private varnish spend a lot of money keeping their car up to this standard and are inspected on the same schedule as all other passenger equipment. The steam locomotive cannot provide 480 volts to the train line, therefore the extra locomotive. The Long Island Rail Road used to have two "locomotives" on its diesel lines so the train could run either way without turning the consist. But the west unit, usually built into an old 4 axle ALCO unit, was not a locomotive at all. it only looked like one. Inside it had the generator for the Hotel Power, and also had the cab controls when that end took the lead, that is to say on all westbound moves. Even so only the east locomotive moved the train, but was controlled from the west unit. With their new equipment the locomotive remains on the east en, but on the west end is a cab coach that can control the train from the west. Interesting, they must have two 'dual-mode' locomotives when going into Penn Station with dual-mode equipment. AMTRAK owns the station and will not allow an LIRR consist to run from the cab car. This is because the LIRR uses a third rail for its electric power, and the train could 'gap-out' if the engineer did not know where his engine was in relation to the third rail. This requirement does not apply to New Jersey Transit or to AMTK, which gets its power from the overhead wire, and this has no gaps Clearly if some one wanted to, they could put that generator in a baggage car or something and then the steam locomotive would look like it was working alone. BTW those steam locomotives that run on any main line do have all of the cab signals and positive train controls as the diesel locomotives. Steam on dedicated tourist routes might not have this. The locomotives out of Steamtown in PA are fully equipped since they do run on active mainline tracks, but still have the diesel to provide Hotel Power. 🦁🦁🦁🦁🦁🐯 broadwaylion.com

[@ehadder]

That’s a great description of Hotel Power. I think this is a great topic for a future video

[@tomcat428cj]

PTC positive train control required on the mainline

[@thinklikeido]

Great video

[@blacquejacqueshellaque6373]

The Diesel is required as all Class 1 railroads require at least 1 diesel engine in a consist for safety. The Diesel is far more reliable than the steam engine, provides electrical power for the train, has a more reliable source of compressed air, and has dynamic braking, which the steam engine does not. This does not take away from what the steam engine is doing.

[@Sparkchaser1200]

The diesels do not provide power to the cars on the UP trains. Freight locos did not have head end power. If you look you can find a passenger Freight car that has a HEP unit installed. That car supplies e-power to the train cars. Amtrak locos also fill this requirement as they all have HEP units, also on the Grand Canyon Railroad.

[@BryanTorok]

It is amazing to me that even those large steam locos don't have has much power are the modern diesel locos. So, not only are diesels cheaper and more convenient to operate, it would be somewhere between difficult and impossible to have 100+ car freight trains pulled with steam locos.

[@austintaylor7363]

Yeah no lol.

[@BryanTorok]

@@austintaylor7363 Sorry, I don't quite know what that means. Are you agreeing with me or laughing at me?

[@austintaylor7363]

@I'm Me maybe where you're from, they wouldn't. But US steam locos would drag 100+ cars with effort not even fathomable. We don't need the diesel electric, we use it as a fail safe.

[@BryanTorok]

@@austintaylor7363 I'm from Ohio. I was basing my understanding on things written by other people on YT and other places. I get that engines such as Big Boy could pull 100+ cars, but Big Boy is at the top of the range of steam locomotives.

[@williammacdonald3173]

I will say 4014 did some brief running in the yard in Cheyenne by itself

[@theimaginationstation1899]

Hi. Aren't you conflating a few issues with tractive effort and power? Tractive Effort is by definition the force a locomotive applies to the rail head at starting. Whereas it's correct to say that any given steam locomotive achieves its maximum power at 'a' speed - or within 'a' particular speed band; rather than saying "at speed" (which sounds like you mean high speed). That "Mike" would by the look of it achieve its maximum draw-bar horse-power somewhere between start and 25 mph - and the 'Consolidation' probably a bit lower.

[@ehadder]

I just wanted to briefly touch on the subject for this video, without going into much detail. I could do a whole new program later just on that subject.

[@theimaginationstation1899]

@@ehadder Fair enough. It's a very technical subject that gets both complicated and interesting very quickly. And is nearly as old as locomotives themselves! And who doesn't like tractive effort?

[@richardnelson317]

I didn't know steam locomotives had that much trouble on the low end. everybody needs help, even the mighty big boy

[@wedge4hire]

Could it be to make sure the train didn't run out of steam?? Or to maybe lighten the load on the steam loco? Or, like the narrator mentioned, maybe a scheduling issue!

[@chucksdesk]

There are a lot of passenger coaches that need a lot of electrical power. I always figured the diesel loco was there to primary supply the large amount of electrical power need by these coaches.

[@tnxrail]

Most of this also applies to Steam Train running on the Main Lines in the UK but the other loco would most likely be on the back and would run as required. Also run both locos at the front if there is a incresed fire risk the steam will run low power for show and the other behind it will do the work. People aren't always happy with another diesel or electric but it has to be done sometimes.

[@volvomad]

A lot of UK tours don't use rear diesels. They are generally only needed where the train needs to be hauled backwards out of a terminus station

[@organbuilder272]

Another train? You mean they couple the cars from two trains to be pulled by one locomotive?? If you know so little about railroading that you call a LOCOMOTIVE a train, you have a lot to learn. Just to enlighten you a little - a locomotive pulls a consist. The locomotive, its tender and the consist is called a train. A locomotive is not now, never has been and will never be called a "Train.

[@tnxrail]

@@volvomad Yeah true it depends on the company to if they have one or not in some cases.

[@davidyoung8521]

Power and HVAC for passenger cars. Steam engines only had power to run headlight and lights on the engine. Passenger cars had their own batteries and wheel generators in the old days.

[@Buck1954]

I've heard it supplies electrical power to the coaches as they require more now, as compared to the days when steam units only powered trains. 844 rescued a diesel supplied freight that stalled on a pass. I don't buy that he big steam locomotives need help to pull. But the diesels are insurance nevertheless. Go back to WW2 when steam locomotives pulled long trains loaded with military equipment such as tanks.

[@Bigbuddyandblue]

Very interesting

[@Ford_Raptor_R_720hp_V8]

*To Reduce Wear and Tear on the Steam Engine,* *and to Push the Steam Engine off the Main-Line in a Timely manner, in case there's a Mechanical Problem.*

[@SgtKilgore406]

9:23 This is where I have problems with diesel locomotives in a train with a steam engine. To me it looks like the diesel is pushing the steam engine due to the lack of smoke, chug sounds, and exhaust steam from the pistons. In the very beginning the steam engine appears to be pulling weight but the amount of exhausting steam from the piston quickly dies down when it starts moving which to me suggests the diesel is now pulling the majority of the weight. These scenarios are what kill my enthusiasm with steam trains. Personally I refuse to ride on a "steam" train that has any sort of diesel locomotive presence. However, the use of generator cars, with zero ability to put power to the wheels, are fine and I understand the need for extra electrical power to cars. But the magic of steam engines for me is broken when diesel locomotives are put on the consist because it is too easy to pull a sleight of hand by making you think the steam locomotive is working when in actuality it is a worthless show piece.

[@ehadder]

The sequence at 9:23 is a train moving downhill on a 1.5% downgrade. Gravity is doing all the work. The steam in the pistons is only there for lubrication.

[@SgtKilgore406]

@@ehadder That makes more sense. Thank you for that explanation! I still stand by the original stance about having diesel locomotives in a steam consist. It is just too easy to pull a sleight of hand in that scenario. At the same time I do agree with needing the added assurances and reliability when operating on main lines with busy schedules. There really is no way around that issue and I can understand it. For me I really want to experience the true steam locomotive journey. The same thing Americans did decades ago when steam still ruled the rails. The best experiences in my opinion are the most genuine. If the train breaks down, runs out of water/coal, etc... then oh well, it happened back then and I get to experience it. Still have plans to eventually tour the Durango and Silverton along with other similar lines where they don't use diesels on the actual routes.

[@ehadder]

@@SgtKilgore406 yep, I can understand your point of view. I was in a steam train in Durango a few years back. We broke down not even half way to Cascade Canyon. They had to use a diesel to rescue us and take us back to Durango. Never even got to see the most scenic parts of the trip. I had been there many times before so was not really disappointed, and they refunded half my ticket price.

[@gregs3153]

Back in the day with steam how did they power the lights on the coaches from the 30s 40s ? And heat

[@ArtStoneUS]

Wood stoves and whale oil lamps

[@kneemeister]

There was a steam line running the length of the train, even diesel locomotives until the 70's had a boiler installed to make steam, the steam was used for heating and AC. Each car had batteries and wheel generators for lighting and or gas generators. Dining cars used wood for the stoves.

[@-randychasechase2660]

Just proves the old steam engines can still do the job!!(

[@23GreyFox]

In my country i see them at the end of the train, if they have any diesel lok at all.

[@patrickwilliamson7185]

Right on the money

[@davidurban6813]

I've got a question, what is that car right behind the engines? Is that like a generator car to supply electrical power to the cars? Just wondering Have a Happy New Year everyone.

[@ehadder]

Yes, on Grand Canyon Railway, we have a 'Power Car', that is just a diesel electric generator strictly to supply 480V electricity for the onboard systems on the Passenger Cars. Even though the former Amtrak F-40 diesels can provide Head End Power as well, we prefer to use the Power Car with the Steam Engine. That way, when we cut the steam engine off at the Grand Canyon to replenish the water in the tender, we can take both the Steam and Diesel together, and leave the Power Car behind to keep the lights on in the Passenger Cars. Otherwise, we have to disconnect all the air and electrical connections between the steam and diesel, then hook them back together, which is kind of a pain.

[@tedlawrence4189]

If steam engines need diesels to run,they may as well keep them in museums,and let the diesels run the tracks.

[@BleuJurassic]

every one looks at starting and moving the train not slow and stopping I think another reason is just that the diesel has more stopping power than the steam I may be wrong so .....

[@garycameron1533]

3985 ran many times without Diesel even with a long consist , even 4014 coupled with 844 runs Diesel , would be great if UP could run 4014 , 3985 and 844 as a triple header , what a sight ...