How the Docklands Light Railway is Powered

Third rail, but with a difference.
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[@Trek001]

"You are the conductor rail to my underslung pickup" Steady now, Jago... Steady now

[@pauljmccluskey5532]

😝

[@mw...]

I heard that and I thought, ‘I beggya pardon?’

[@djtraxxehv1058]

@Trek001, nice one!

[@vincentlugthart4618]

Could be worse: you are the shoe to my bottom contact

[@djtraxxehv1058]

@@vincentlugthart4618 true as well ;) good one as well :)

[@thefareplayer2254]

I’m a simple man. I see Jago, I click.

[@jokmapola5255]

I identify as a Epson printer and as such, I am the same.

[@terrycostin7259]

I totally agree my friend .

[@LittleWittleKitty]

I’m a simple lady. I see Jago, I click.

[@blazaram3368]

Same

[@miguelbarreira5005]

Samesies

[@namenamename390]

Fun fact, the DLR train in Manchester mentioned was not the only one to be fitted with a pantograph for overhead wires. Some of the oldest DLR trains were sold to Essen, Germany to be used as tram trains, so they were fitted with proper driver's cabs and pantographs.

[@Name-iq8te]

wasn't this to do with the bank extension and some sort of health and safety legislation? x

[@namenamename390]

@@Name-iq8te The German Wikipedia article I've read to make sure I wasn't misremembering said that the old DLR trains did not meet updated fire safety standards in Britain, so they were sold off.

[@Name-iq8te]

@@namenamename390 thank you :)

[@simonwinter8839]

​@@Name-iq8te What's with the kiss.I didn't know you cared x.

[@railotaku]

@@namenamename390 I gather the Kings Cross fire led to a tightening of the rules rather than the expected relaxation, and as a result the walkways in the Bank Tunnel were deemed not compliant so end doors had to be fitted. Generally if there is sufficient space alongside the train end doors are required - this is why Thameslink needed them for Moorgate (the rest of the network is fine) and there had to be a lot of work moving track in the tunnels around Dover to allow Javelin trains to operate.

[@morzee94]

“I realise it’s extraordinarily nerdy to have a favourite rail system” - Jago, remember who your audience is. We all have a favourite rail system haha

[@andrewmcgee382]

And most of us see nothing wrong with being nerdy!

[@althejazzman]

If we were put off by videos that were extraordinarily nerdy, none of us would be here. It's exactly why we're here. I applaud your choice of favourite railway.

[@jlr108]

I emigrated from the UK in 1984 and have only been back occasionally. I'd heard of the DLR but had never had any reason to think of using it until one night, about 7 years ago when I was in the West End, the trains from Charing X to southeast London where I was staying were cancelled and a friend suggested taking the DLR from Bank to Lewisham. I fell in love with it right away - that magical ride through all the tall, lit-up glass buildings was a wonder. I had never been to Canary Wharf before and it was really quite a spectacle in the night. Was back in the UK last summer and had to try out the Elizabeth line, so went to Canary Wharf to have a wander around. Sadly, my sister who I used to stay with in Eltham when visiting passed away so I don't know when next I'll need to use the DLR again.

[@dukeofaaghisle7324]

For the first 80% of this video I kept thinking “yes, but what’s that wire between the running rails?”. I am so pleased you answered that question. It was nagging at me. I shall have to watch again now and give my full attention.

[@berndf0]

In Germany U-Bahn and S-Bahn systems with third rail power have been using pick-up from below has been introduced around 1910. That is when the Hamburg "Hochbahn" (now called U-Bahn) and the first Großprofile-lines of the Berlin U-Bahn opened. The only lines I am aware of that use pick-up from above are the older Kleinprofil-lines of the Berlin U-Bahn, which opened in 1902.

[@Martindyna]

Yes I'm not sure why Jago didn't mention that the insulated top 3rd rail has been the norm on the Continent for decades, perhaps he wasn't aware.

[@SteamCrane]

Under running third rail has been used in the US for well over 100 years, primarily in the eastern metro areas, for engines on mainline trains, and MUs.

[@thexalon]

I'm glad to learn all about the potential and current options for electrification. Of course, there's some resistance to the idea.

[@trigfanorthwales]

I see what you did there 😂

[@davidioanhedges]

Please continue to enthusiastically enthuse about things you are enthusiastic about ... It's why we are here

[@calbal91]

Driving the DLR is truly one of life's great pleasures

[@hairyairey]

I once had the keys in my hands. I gave them back though! Not before exclaiming "Just what I've always wanted, my keys to my own DLR train 😂". Fortunately PSA laughed too

[@philipgibbard304]

Thanks Jago. The third-rail system with a contact from beneath is quite common abroad. It's used on the extensive Hamburg S-Bahn system for example.

[@sjokomelk]

It is the de-facto standard for all metro systems around the world. And has been since the 50/60s.

[@JohnADoe-pg1qk]

And the Berlin S-Bahn and some lines of the Berlin U-Bahn. The other U-Bahn lines use a third rail with contact from above. They don't mix because the height and width of the trains is different but they have the same track gauge

[@musiqtee]

Yep, Oslo and Stockholm metros were (mainly) built in the early 60’s. As Jago does mention, a ‘bare’ top-pickup rail wouldn’t work up here - it’s actually snowing _now,_ bloody April fifth… 😅

[@IamTheHolypumpkin]

Unfortunately your comment is false. Hamburg S-Bahn does pick up from beneath but even stranger. It picks up from the side. The inner side towards the running rails. Sone sections are too electrified with overhead wire and all new lines are build with overhead wire. The S-Bahn Berlin is similar. It also picks up from the side (which I, didn't knew myself). But it has an even Stanger trick up it's sleeve. At a few locations the bridges are too narrow and the pickup-shoe could hit the bridge. To prevent that, they can flip up the shoes to get the required clearance. I'm no longer sure is done from the drivers cab or using trackside equipment, but I think I recall it trackside equipment. Small fun-fact about the Berlin S-Bahn. The reason it uses 3rd rail is, because the system is so old, that back in the day where the build the first lines, lobbyism of steam locomotive manufactures lobbyed hard to prevent bridge to be raised with the intend to prevent overhead wire to be build. Berlin U-Bahn is also kind of crazy. The "Kleinprofil" i.e. The narrower cars on the Lines U1, U2, U3 and U4 are top pick up with positiv polarity. Except U2 it has negativ polarity because of the Berlin wall. The "Großprofil" the wider trains are all with bottom pickup and have a negativ polarity.

[@dodgyvideo]

BART, which is commuter rail for the San Francisco Bay Area (Bay Area Rapid Transit) uses the same system, whereas San Francisco's Metro uses overhead wires, as it's a hybrid tram/underground service.

[@hassanraja]

This is crazy - just this afternoon I was staring at the DLR tracks trying to work out where the power was coming from!

[@AndyChamberlain-e6u]

Guess what, I was doing exactly the same on Thursday! Thanks Jago for illuminating the subject

[@adrianrutterford762]

Thank you Mr H. Not only full on nerdiness, but a “Cheerio” at the end. Excellent Friday Fun.

[@ROBERTNABORNEY]

Washington DC used a buried conduit system. Everyone called the current collectors "plows" Back in the Sixties, the model railroad I belonged to was building a rapid transit line based on the Hudson Tubes (officially the Hudson & Manhattan Railroad). We had a very senior member who started model railroading in the Thirties when outside third rail was standard for models. He VERY strongly recommended an overrunning system, having tried (emphasis on tried) way back then to develop an O Scale underrunning system to be prototypically correct for a model of the New York Central's Grand Central Terminal electrification. We followed his advice!

[@roberthuron9160]

Jago,there is a New York connection! The New York Central,when electrifing Grand Central Terminal,came up with the Wilgus-Sprague third rail system,which was the original operation! It was used on the Market-Frankfort Elevated in Philadelphia,and the Berlin S- Bahn,and other European operations! Short note,thank you,for your peripatetic sidelines! Thank you 😇 😊!

[@brianfretwell3886]

I was a victim of snow on the third rail once. In those days between Loughborough Juntion and Blackfriars they only used the centre pair of track ouside peak hours. It had snowed overnight and I was on the first train of the day to use the outer track. A mile or so out of Elephant and Castle the train slowed to a halt. After a few minutes it carried pn. It would seem that snow had isolated all four pick up shoes and after while they had melted through the snow and picked up current again. This happened a couple more times and as we got ito Elephant and Castle station platofrm 1 we were told that the train had been cancelled and that we should go to platform three to catch the next train.

[@nathansvlog]

I'm a total dork about traction current and I'm so glad you're covering it - do you think you'll do one exploring the fourth rail system on the tube? Something interesting about it in particular is there are some sections of tube where they outer rail carries the entire voltage and the middle rail is a 'return' like you say, but other sections actually split the voltage to +430 volts on the outer rail and -200 on the centre rail. It's the first time I've ever thought about the concept of receiving a 'negative' voltage shock, but potential difference to ground sees a 200 volt shock either way.

[@chrisstephens6673]

I would ask why they change the side of the rail at stations, OK its to put the live away from the platform but why not keep it on that side between them?

[@RogersRamblings]

@@chrisstephens6673The positive rail changes sides to even out shoe wear in addition to reducing the danger factor at stations.

[@chrisstephens6673]

@@RogersRamblings but it is almost exclusively on one side, except for a short section in the station so how is even? Not being argumentative but if that were to be the reason why not more even?

[@msg5507]

Jago has made a video about the Underground's 4th rail system, in June 2021.

[@StupStups]

Apologies for nit-picking but the voltages are in a 2:1 ratio, so it's +420 and -210, giving total traction voltage of 630V. There is a slow move towards 750V across the network but that is also in a 2:1 ratio.

[@Lego6980]

4:06 woooo! Jago. Nice rare pic there!

[@MrGreatplum]

You call this nerdy, I call it fascinating! Thank you, Jago!

[@jamestoyn9755]

The docklands' light railway opened in the same year I was born in 1987. Unfortunately, I wasn't around during the opening of the railway, but I do remember riding the train to the original island garden station.

[@lassepeterson2740]

Born 3 years too late .

[@jamestoyn9755]

@lassepeterson2740 I was just wondering why does the DLR train's wobble from side to side when going along the track.

[@hughs591]

Admirable brevity, small is beautiful; like the DLR!

[@lawrencelewis2592]

In Toronto, the subways are powered by an over-running third rail system and these all have a covering plank, even in the tunnels. I recall that after a heavy snowfall in New York that the lines with over-running ( the Long Island Rail Road, as I recall) could not operate but the under-running lines like the Metro North could.

[@ElfShoes5]

Loved the Tyne and Wear metro shoutout!!!

[@johnburns4017]

Is the Tyne and Wear moving to heavy rail trains? Stadler, based on the Merseyrail 777s?

[@hairyairey]

@@johnburns4017 No, new trains are very similar to the old ones with most if not all of the design flaws sorted. It's actually surprising that they haven't extended to three trains, but that's going to require another depot.

[@Martindyna]

@@hairyairey I hope you can still look out of the front window on the new trains.

[@hairyairey]

@@Martindyna unfortunately not, the new cabs are the full width of the train. I used to sit at the front chatting to the driver as they would leave the door open. Different times!

[@Martindyna]

@@hairyairey What a shame! Why remove a much loved feature, well I guess you answered that one, may disturb the driver. As you say, different times.

[@mw...]

Always a delight. The cheeky euphemisms at the end are the best part

[@ROBERTNABORNEY]

Congratulations on catching up with the US. The New York Central was using underrunning third rail on the Grand Central Terminal project around 1910.

[@SteamCrane]

...and for much heavier mainline passenger trains.

[@julianaylor4351]

I was once on a Euston to Watford Overground train, that was struggling to move in snowy weather, so the DLR's solution, is a very good idea, given that when it snows in London, and then settles, outer London areas suffer, especially near large open spaces.

[@vaclav_fejt]

Prague Metro is also powered by the bottom-pickup third rail. I did wonder how the pickip worked when the rail was so bumpy on the upper side...now I know, thanks, Jago!

[@terrycostin7259]

I worked on it , great taking grandkids and friends on , keep up the good work JAGO .

[@paulgoodman8476]

Oh, Jago - your extraordinary nerdiness is one of your most redeeming qualities!

[@driver288]

This means that the DLR used pretty much the same design as the Stockholm metro. Also 750v DC bit varies a bit between the lines where the latest lines have a little more power. Delivery is through a 3rd rail on the side slightly elevated compared to running rails and covered by a wooden plank rather than plastic. Also the 3rd rail alternates sides and is always on the outside of the train at stations.

[@neilbain8736]

Short and sweet and answers exactly what I've always wondered. The centre rail looked too flimsy for the current necessary and the outer one was a plastic tube with all these bumpy brackets. It took me ages to suspect the pickup must be underneath and inside the tube.

[@rainyfeathers9148]

Thanks, I was actually wondering what that skinny wire thingy was😅

[@threeparots1]

Skytrain system in Vancouver uses this as well. Called leaky coax. Skytrain uses two of them in parallel due to the centre LIM reaction rail. Though I think they cross the leaky coax over for location tracking identification. Canada line which uses more tradition cars only has the one wire. Skytrain also uses a forth rail system due to train Ms lifting slightly when pulling away which makes for a poor grounding through the rails. Complicated but it is reliable and can climb decent grades.

[@supermanifolds]

Always loved the DLR and in learning this I now have yet another reason to love it

[@Steven_Rowe]

There was a third rail line from Manchester to Bury. It was electrified at 1200V DC. Interesting in Australia there is a new Metro Line in Sydney, it is fully automated so driverless but uses overhead at 1500DC, the line is being extended this year and also firther in 2025 plus a new western suburbs metro from Sydney to Westmead via Parramatta.

[@junovzla]

in Caracas Metro the third rail is covered with a plastic tube so that it solves both problems of debree and protection

[@SilverScroll]

The bottom-pickup conductor rail is actually how almost all German third-rail systems work (Germany has no mainline third-rail-equipped lines, only metros and metro-like systems). The one exception I can think of off the top of my head is the older "Kleinprofil" underground lines in Berlin, which use the traditional top-contact variant. Speaking of DLR trains equipped with the ability to use overhead wires - would you be interested in making a video about the former DLR vehicles that ended up being sold to Essen in Germany, where they were converted and are still in use today, as well as why that sale happened in the first place? I've ridden on those, and it's quite a sight to see the builder's plaques in the interior of a vehicle in Germany listing such an origin.

[@simonwinter8839]

Originally the DLR was to be powered by a hamster on a treadmill but the network got too big. I'll get my coat !!

[@Mk99987]

In New York, Metro North, the former NY Central commuter lines,uses under running third rail. supposedly, it is to prevent problems with heavy snow.

[@iankemp1131]

Third rail actually has a very good safety record. Platelayers know well that before you go anywhere near the lines to repair them you make well and truly sure that the traction current is off. Same as the Underground. On the other hand, a side contact 3rd rail system was pioneered back around 1915 by the Lancashire and Yorkshire Railway on the Manchester-Bury line. It ran happily enough but was converted to the Metrolink when the non-standard rolling stock became life expired.

[@hairyairey]

Third rail is responsible for eight times more incidents than OHLE according to the HSE

[@johnchurch4705]

@@hairyaireyis that track workers or people trespassing?

[@hairyairey]

@@johnchurch4705 probably both. I recall someone dying as they were running away from the police.

[@russellplumley8665]

I thought the juice was only turned on block by block as the train entered the block, so roughly speaking, no train coming, then power in the third rail.

[@russellplumley8665]

"no power"

[@James_smith940]

The Amsterdam metro uses the same system. Took me a while aftrer moving over here to work it all out.

[@andrewemery4272]

The under-rail pickup method is itself over 100 years old. In 1919 Vincent Raven planed to use this pickup method for his proposed York - Newcastle electrification.

[@ROBERTNABORNEY]

That's nice. The New York Central employed underrunning third rail on the Grand Central Terminal project - more than a decade earlier

[@BritishBeachcomber]

I remember the line from the '60s, with my best friend, son of the rector of All Saints Church, Poplar. Happy times, sleepovers at the rectory, trainspotting, Twin Rover day tickets.

[@rowanmorgan457]

Always wondered about this. The DLR is my most used bit of TfL. Thank you Jago!

[@lexifillems]

Just spent a couple of days in London. I felt I noticed quite a lot more interesting things as a result of watching your videos. 😊 DLR was really convenient (I was staying near Royal Albert station) except when they closed for planned work at the weekend. 😂

[@09021983]

The cable in the middle is called the inductive loop

[@johnm2012]

Does it actually form loops or just run parallel with the rails, as it appears to do in the video?

[@johnburns4017]

It is a control rail, not a power rail.

[@simonfwhawthorn]

A bunch of the old DLR trains that ended up in Essen have been converted for "tram" running along a section that goes above ground and along streets. Didn't manage to get out ot that bit to see how they power that bit. May have to nip back and check some time.

[@TheInselaffen]

At last, Jago reveals to secrets of the elastic trickery!

[@charlotteistance4386]

No reference to the Victora to Bury line in Manchester? That used a side pick up 3rd rail similar to the DLR didn’t it? Love your work Jago xx

[@ADAMEDWARDS17]

Side contact and much higher voltage at 1200vDC, so uniquily different for the UK. I used to travel on it to school.

[@alfigel2567]

"Well, You shouldn't have been on the line in the first place" 😂

[@chrisaldridge6185]

the conduit trams in london had 2 conductor rails the plough pick up ran between the conductor rails

[@ncliffordjr]

great video! I've always been curious as to the DLR's power situation, especially because (as an American) when I hear "light rail" I think overhead wires, but obviously there aren't any on the DLR! bottom-contact third rail is also pretty neat, I believe the LIRR commuter lines in New York use that as well

[@Adam-wl8wn]

It's basically the same as the Heathrow and Gatwick track transit systems. Only difference really is they run on pneumatic tyres but they still follow a powered guide rail.

[@mikemetaled]

Weird how I was on my way to the ExCeL this weekend wondering why there are no dire warnings in the stations themselves not to stand on the third rail, only the usual "risk if you pass this point" signs at either end. Then at the exact same time Jago answers the question.

[@stephenbond1990]

Fun Fact about 3rd rail electrification under the Southern Railway between the Grouping and Nationalization. There were gaps in the conductor rails around infrastructure for steam traction, I've got a book of old black and white pictures of steam operation along the old SE&CR lines in London and Kent and there's a photo of a 0-4-4 tank engine pulling a passenger train stopped next to a water column on a line with 3rd rail electrification with the engine's coal bunker more or less in line with the water column and one of the crew on the ground. The caption specifically points out the gap in the conductor rail as being for the convenience of steam engine crews, which is concerning as most of the length of the gap is parallel to the engine with only a short stretch reaching roughly to the bogie of the first coach. If that was the norm and not a one off I feel sorry for the poor bastards manning the steam commuter services in south London.

[@isashax]

That's a fab explanation! I also love the DLR.

[@ignacioverboten9382]

That looks reminiscent of “New York Central” style 3rd rail that is still in use in the Metro-North system today East of Hudson. The system travels about 50 miles north of New York City with sections that have at-grade crossings. It’s definitely a commuter rail system with I’d guess approximately 2-5 miles between most stops. I think the trains get up to 70 MPH in some rare sections, but usually stay below 60 MPH. I believe the voltage is similar, ~750VDC. The easternmost line, called the New Haven line, enters into Connecticut. Before crossing into Connecticut, as the trains have to transition to the Northeast Corridor line, the trains on that line transition from using NY Central 3rd rail to Overhead catenary compatible with NE Corridor electrification. The train cars also appear to be about double the length of the DLR cars in your video. The consists are definitely much longer, usually being 8-12 cars I think.

[@josephturner7569]

The change over from shoe to pan is quite interesting

[@edrubin6042]

It's odd to me that underslung 3rd rail shoes are a novelty because I grew up in New York where it is common. The Subway, the ex NY Central rail lines, and the Long Island Railroad use this style. The New Haven uses catenary, and has a lot of unelectrified rural lines so their commuter trains are triple powered with catenary and diesel for operating on New Haven track plus third rail for operating in Manhattan and Grand Central Station.

[@a133m210]

omg you did actually do this video now!!! Good!!

[@williambecwar7939]

Hello Jago... Have you ever heard of the Chicago, North Shore & Milwaukee interurban? Called the North Shore by it's friends, this interurban line ran 90 miles between downtown Chicago and downtown Milwaukee. The center of Chicago part was on the Chicago Elevated, which mecessitated third rail operation. But north of suburban Skokie, the line shifted to overhead, something done on every powered car on every ttain. And the change was handled manually by conductors and collectors (the rail personnel, not electrical components). They had to quickly get trolley poles on the overhead wire, in any sort of weather, while the train coasted along at 35 mph. Nowadays, such a power swap could be handled with pantographs at the touch of a button, but where's the fun in that?

[@PenryMMJ]

It's a clever system and makes a lot of sense. I'm still rooting for electrified steam trains though. Look at that magnificent steam train at the end. Wouldn't it be chuffing great to see those going past knowing that the steam boiler was running on electricity? 😁

[@simplesimon2802]

Switzerland did this during ww2 and in the late 1930s / early 1940s the USA was experimenting with steam locos that generated their own electricity - but without success

[@mickeydodds1]

Hornby make or maybe made a line of model railway locomotives which 'electrically generated' their steam propulsion.

[@hairyairey]

Wrong way round. Make a steam engine that powers a steam turbine and makes its own electricity! Bonus points for a nuclear reactor...

[@pj_naylor]

I seem to recall stories of stations at the outer reaches of tbe underground keeping a short section of track, with insulated handles, to short out the line and de-ice it in the winter.

[@lazrseagull54]

I struggle to pick a favourite rail system but the DLR is certainly one of them and probably my favourite in the UK. I hope they follow through on the plan to extend it to Victoria and add a Tower Hill station in the Bank tunnel so that all 24tph can serve the entire core route where they're needed.

The DLR vehicles thet were sold to Essen in Germany in 1991 (P86/P89 series) were also converted to using overhead wires.

[@hairyairey]

1500VDC?

@@hairyairey 750/800 V DC

[@phillgreenland2390]

It's absolutely my favorite rail system too!

[@deeser]

I don't even live in London, but thanks to you I know not about the trains there than my mates who do. Top stuff!

[@pauljmccluskey5532]

Hi Jago, the concept of a tram down Mile End Road would make great sense! Travelling along there is an absolute nightmare and takes a good hour to get from Stratford to Aldgate.

[@imsbvs]

Never used to take so long, must be related to being limited at a snail's pace, ie 20mph. Especially when there is very little traffic.

[@pauljmccluskey5532]

@@imsbvs It did seem loads longer on a busy day though

[@hairyairey]

The Mile in Mile End refers to the distance to Aldgate. It's therefore just 1,000 Roman soldier paces

[@WardyLion]

A long time and very dear friend of mine once lived in Lewisham and it was visiting her that first brought the DLR to my attention.

[@MrBlopshotted]

same system is used on the Oslo metro, but I only realised after watching this video. Thanks Jago!

[@timhubbard8895]

Nice video! I like the DLR too!

[@_Rhort]

We love you, Nerd! xx

[@eattherich9215]

It's not witchcraft, then? I'll get me coat.

[@GeorgeChoy]

Jago, you can never be too nerdy for railways.

[@emjayay]

Yeah, just check some of the comments.....

[@ageekdude]

When I traveled to Berlin, I noticed that U1-4 had traditional third rail but U5-9 have a similar under-rail pickup

[@Dan-Athema]

A similar system was used on the line from Bury to Manchester before it was converted to a tram. Class 504 units used a side pickup.

[@teecefamilykent]

Great video sir, I love the Glasgow Subway lol.

[@radiosnail]

Extremely interesting. Many thanks.

[@peterelvery]

Informative and entertaining as usual. It's not so much the third rail itself that necessitates frequent electricity supply sub-stations. It's the safer low voltage that third rail requires.

[@MichaelCampin]

KZbin are messing around it took me 10 attempts to get volume

[@peternorris6438]

Great video and informative and interesting

[@mattmclafferty6265]

Interesting Jago. Thanks for all yr vids. Gauranga

[@jonistan9268]

As far as my understanding goes, the short distances between electrical sub-stations isn't because of the 3rd rail system, but because it is a DC system. DC powered railways that use overhead wires have the same problem as far as I know.

[@norbitonflyer5625]

Inded - it is the low voltage: although overhead DC systems are usually at higher voltages than 3rd rail - typically 1.5kV or 3kV, this is still much lower than AC systems which typically supply at 25kV. The reason is that low voltages are needed for the traction motors and other systems on the the train, but there is no way of changing voltage in a DC system - transformers only work on AC. Transformers (and rectifiers, to convert from AC to the DC the traction system needs) are heavy and bulky, so add to the complexity of the trains. But transmitting electricity over long distances at low voltages results in more losses in the transmission system, so the substations need to be clsoer together. So low voltage DC is more suitable where there are lots of trains within a small area, and high voltage AC when there are fewer trains traveling longer diustances.

[@paulketchupwitheverything767]

I didn't realize that no new 3rd rail lines ( 1:51 ) are allowed. Has this this ever led to any difficult situations around wanting to use the same type type of trains on neighbouring lines or what constitutes an extension of an existing line versus a new one? I've seen that Thameslink trains switch between 3rd rail and pantograph to operate on either. I understood this to be because the alternate systems were historically used in the different regions: north and south.

[@luisstransport]

Great video Jago

Very informative, thank you.

[@lordmuntague]

If you've travelled on Manchester Metrolink between Victoria and Bury, then you're on a line which until the 1990s used a very unusual 1200 VDC side contact system.

[@andrewrevans8496]

Ha - I came into the comments to post that! The first L&Y electrification was Liverpool to Southport, later extended to Ormskirk, at 600v DC third rail. The suburban lines out of Manchester were to be tackled next, but because of the hillier terrain 600v wasn’t regarded as powerful enough. The weird side contact arrangement was arrived at partly for safety reasons, but mainly to reduce exposure to snow and ice.

[@lordmuntague]

@@andrewrevans8496 Was it also to reduce the number of feeder stations required? I was under the impression there was only the one input, at Bury?

[@andrewrevans8496]

@@lordmuntague not sure, but I wouldn’t be surprised

[@IgnatSolovey]

Actually the side third rail is MUCH more common than the central third rail used on the UERL lines. Ans safer in case of a passenger falling onto the track.

[@ianhudson2193]

The wire between the rails does not transmit data....it is merely a timing loop split over set distances so trains can judge their speed and heading. Data transfer goes through Docking Data Links, the flat, brownish boxes situated inside the running rail.....

[@UnseenSpirit]

Each carriage has 2 conductor shoes (shoe gear). Only one shoe needs to be in contact with the conductor rail for the trains to be powered

[@Jimyjames73]

Interesting = Thanks for sharing Jago 🙂🚂🚂🚂

[@jamesgilbart2672]

Interesting! As I understand it, extensions to third rail are permitted so electrifying some of the isolated diesel routes/branches in the south of the UK could be allowed but it is more probably prevented by a lack of funds.

[@UnseenSpirit]

The conductor rail is protected by a carbon fibre shroud BTW. I'm a PSA and that was taught to us during training.

[@RaspberryWhy]

Cheers Jago. Can you do something to explain the DLR signalling system. I realise this is even more nerdy than this short film, but driverless systems and safety requirements fascinate me

[@spectro742]

I used take the DLR with a friend sailing in the docklands every Sunday. We would wait at the end of the platform at Lewisham station and get the seats right at the front.

[@OpenbaarVervoer2D]

That way of 3rd rail pickup is commonly used with metro systems across Europe. In The Netherlands we have the same configuration albeit not (yet) fully automated. I believe the North South Line 52 in Amsterdam will be automated in the near future as wel as getting platform doors.

[@Damien.D]

The conductor in plastic conduit was also used to power the electric prototypes of the french air cushion Aérotrain (the "S44" in France and the Rohr TACV in the US). It looked much the same, with aluminium supports, and was orange when new, and faded in a kind of pink just like these. But there were 3 conductor in a triangular arrangement : it was 3 phase power. I'm not a Londoner but your DLR is cute, i'm still baffled it was possible to automate such a complex network, with branches, loops...

[@neeelix]

'Extraordinarily nerdy' - phrase du jour

[@jgodfrey546]

Most informative! FWIW, the tech term for that type of power source is "under-running 3rd rail", since the shoes get their energy in the manner you describe..

[@tallthinkev]

Young Jago is wrong, it's hamsters, lots and lots of hamsters