0042 Scale speed of Dapol HSTs (and a Kato 800)

[@kellypaws]

The HST is actually capable of a higher top speed (148.5 mph). The line restrictions keep it to 125. So, the Kato, arguably, is actually far more correct. Interesting video again!

[@endoorrailway]

Thanks :) Yes the HST holds that speed record, though if I remember correctly it was a 5-coach set that did that record. But if you want to model what HSTs do on the railway you only need it to go as far as 125 Mph... and in the case of the plain blue Dynamic Lines and the Castle set power cars they actually have MTU engines, not the Valenta ones that set the record, so I don't think anybody knows what those ones could be capable of. Same for the IET - there were concerns they wouldn't be able to keep to the timings of the HSTs over the hills of Devon when on diesel-only.

[@willsngaugetrains]

Very interesting video, I did some similar tests using camera frames to calculate the speed with some of my HSTs a few years ago. What I found the most interesting was the difference between the older power cars and newer ones. As of 2020, Dapol changed the motor they used in these sets to a 'super creep motor', and while the slow speed running is much better, it does compromise the top speed. My older models were achieving a good 150mph with a full set! But they are quite inconsistent, some would do 150mph, but others would struggle to reach 100. So maybe the new motors are better overall?

[@endoorrailway]

Thank you :) That's interesting - you continue to be a source of good stats on Dapol HSTs! I've just calculated the scale G force around the corner on my layout (7.6G!), and it's got me suspecting that very few people have such large sweeping curves on their layout that a scale 125Mph would be appropriate for the turns, so maybe a motor that performs better at lower speeds is the better choice. I certainly like being able to drive them slowly into and out of the sidings, so if it's one-or-the-other I think smooth when slow but not quite a fast enough top speed it what suits me.

[@JamesPetts]

I approve of Monty Python references. If you want to increase the speed, incidentally, and you are using DCC, you can always just increase the track voltage.

[@endoorrailway]

Thanks - I couldn't resist, and thought there'd be people who'd recognise it 🙂 I don't think I can change the voltage at the track - my Gaugemaster system outputs 13V, and the NRMA specifications for DCC say it should be 12V for N gauge, but you make a good point because it should be possible to adjust how much of that the decoder lets the motor have, so it's possible it's not giving it the full 13V when at max speed step. I might look into that in future - thanks!

[@ngaugefouroaksstreetstatio6932]

Well that was fantastic and i notice when standing over a layout the speeds seem to be slower but when viewed at board level they seem faster. The youtube video editor allows the magnification of the time lapse but the set up with sensors and laptop is brilliant and amazing how they increase as they warm up.

[@endoorrailway]

Thanks 🙂 Ah, good to know about the YoutTube editor - I've never considered that before! Yes the increases are odd - it's as if the motor benefits from a mini running-in each time the loco is used.

[@toucan221]

slow or fast its lovely to see these Trains go round and Yes I did believe these looked fast close to their known real world Speed

[@endoorrailway]

Agreed - I do like seeing HSTs on the move :)

[@iansngauge]

Hi Jonathan! Another really interesting video! Funny, but I always think my model trains run far too fast rather than too slow! Interesting observation about the difference in model and real life speed though! I wonder what it would look like if you mounted a camera to the train looking at right angles to the track? Would probably seem much faster! I was going to mention the Super Creep motor in the newer HST sets, but someone beat me to it! It's the same motor that's in Dapol's class 33, and is super smooth at slow speeds! I wonder why the motor speeds up though? I can't think of a plausible explanation unless the momentum settings act for a lot longer than we think they do!!! All the best, Ian.

[@endoorrailway]

Hi Ian, thanks :) I tried to capture some close shots for the start of this video, and in those I think the Castle set does look a lot faster, so I think you're probably right about how it would look from a side-mounted camera, though I suspect even then I'd need to be viewing the footage in I-MAX to have the same effect as real life. Yes the gradual increase is odd - I don't know enough about exactly how the motors work to come up with sensible theories, but I'd be very surprised if it were the DCC acceleration - if it were that then it's following one acceleration gradient up to very nearly top speed, then suddenly switching to a massively shallower gradient to do the last little bit, and both the Dapol and Kato (different decoders) behave that way. But, my curiosity is satisfied for now where scale speeds are concerned :) Now I'm waiting for my Sonic Models Large Prairie to arrive :)

[@iansngauge]

@@endoorrailway - Ah, I'm also waiting on the Large Prairie which will be a loco from a new manufacturer to me! I think I ordered the wrong decoder for it though as apparently it needs a 6 Pin 90 degree decoder, which is something I'd not come across before! Oh well! Just another path to follow on my model railway journey! Cheers, Ian.

[@endoorrailway]

Yes, I only noticed the other day the description mentions that, but the one I found at Rails was out of stock so I've ordered it from TMC. Today I've come home to the loco waiting for me :) I won't have time to play with it today though, so the decoder's got another day to arrive! I must have put one of those in my Sonic Models 56xx because that has the same note in its description, but I don't remember it at all!

[@iansngauge]

@@endoorrailway - Mine just arrived this morning! :) Just off to look for a new decoder with RailCom now... Ian

[@MrCalland]

Wonder what the G force would be on the trains going round your corners on your set to scale

[@endoorrailway]

It would make N gauge people uncomfortable - I did a Google search for the calculation, which gave this formula: "Cornering G force = speed (mph) squared / corner radius (ft) / 14.957" At a scale 125 Mph on my layout that's a scale 7.6G!

[@MrCalland]

7.6g woo best get Gforce suits with the train tickets might explain the ticket prices haha

[@endoorrailway]

lol yes, I think it even just about out-does Formula 1! My railway doesn't have any people at the moment, maybe for the best.