1. This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn More.

Some Thoughts On The Ntp Class 101 Dmu

Discussion in 'PC Discussion' started by Trim, Jan 25, 2020.

  1. Trim

    Trim Active Member

    Joined:
    Jan 24, 2020
    Messages:
    143
    Likes Received:
    188
    I am new to Train Sim World; well, I'm pretty new to train sims in any form after an unsuccessful foray into Train Simulator some time ago. But having some enforced leisure time with a sprained ankle I thought I'd give TSW a go and immediately started on Northern Transpennine - easily the route most of interest to me. After starting with the Peak and 47, I had a go with the 101 and, quite frankly, I was bowled over.

    I've never driven a DMU in real life, but many years ago I used to drive trains with similar mechanical systems: fluid flywheel, freewheel, epicyclic gearbox and vacuum brakes, and I am of an age to have travelled many thousands of miles in DMUs as a passenger, usually sitting in the seat behind the driver. TSW's 101 has got the feel just right in my view. I wonder if the gear change might be a little too quick (as I recall, there was a delay of a couple of seconds after selecting a gear before it would engage and the driver could rev up again), but the power notches, the rev decay and, most of all, the vacuum brake feel just right. The way that dropping the first few inches appears to do nothing at all, just takes up the slack in the brake mechanism as it were, and you need to go to about 15 inches to have an effect. The way lap works, exactly as I remember it, including the telltale bounce on the train pipe gauge when you put the handle into lap as the remaining vacuum evens itself out (vacuum is vented from the front of the train, and unless you vent all the vacuum, there is always more vacuum in the back of the train than the front during a brake application). The four- and six-car sets take appreciably longer to both dump the vacuum and restore it when you release the brakes than a two-car set. I have no idea if the timings are right, but they don't seem obviously wrong. Even though we have the / key for lap, I rarely use it because I particularly like the way the ; and ' keys "stick" at the lap position, in about as close a way as you can get on a keyboard to how the physical brake handle behaves. In short, the 101 is a delight to drive...if only it could keep to time.

    Okay, so I am new to this game, new to train sims, and I am clearly not the best driver in TSW, but I don't see how anyone can keep time with the 101 in the Northern Transpennine timetable. With this bugging me, I've done a little investigation, and I can straightaway say that there is nothing wrong with the service timetable, at least, not in respect of DMU timings (there are other things wrong with the timetable and I'll probably write about these in a day or two). I've been making notes of the timings in the current in-game timetable and I have a scan of the 1982-83 passenger timetable, and the timings match almost exactly.

    Something else I don't think is an issue is the 30 second enforced station stops. I've read other users complain about these (although I think this was in relation to a different route). As I recall, trains did stop for 30 seconds. Even if there was no one waiting to get on, guards had to wait for people to fight with the door catches and let themselves out. Perhaps some stops would be less than 30 seconds, but these would be compensated for by others which were significantly longer.

    So, having ruled these out as problems, I looked closely at how the AI drives trains. The AI keeps to time - it really does. At first, I wondered if AI-driven trains only spawned when a player was around, naturally spawning at the appropriate time and place to match the timetable. However, if you ride on a DMU from Manchester to Leeds, it keeps time all the way, and it does not appear to break any speed limits (in fact, it usually sits a few mph below the limit, so far as I can tell from the speedo). It is clear that the AI does not need to worry about gears; there is no dwell at 25 and 40 mph on a rising gradient when changing from 2nd to 3rd and 3rd to 4th. In fact there is no dwell anywhere, just a smooth acceleration. Could gear changing be the key? Well, partly. Certainly the AI saves some time by not changing gears, but it also has noticeably faster acceleration, even when no gear changes are involved. On the return Saturday Special working starting from Stalybridge, I could only get the train to 34 mph as we left Stalybridge Tunnel, whereas the AI managed 41. Okay, that might be my poor gear changing, but it then took me 80 seconds to accelerate from 45 mph to 55 mph while the AI did it in a mere 40 seconds. Deceleration times during braking aren't so noticeably different although the AI does have the edge, except that I don't think this really compares like with like. As with perhaps most TSW 101 drivers I've got into the habit of dropping the lot between half a mile and a few hundred yards out from a station, depending on the speed and gradient. This might help keep to time, but it is not a good - or safe - way to drive, effectively making an emergency brake application for a routine stop. Under normal circumstances I'd expect to lap at 5 inches or thereabout for what might be classed as a "full service" application, and then the braking is considerably slower than the AI.

    So, what do I think needs to happen? As I say, the feel of the 101 seems right to me, but it's acceleration and braking are too slow. My guess is that a simple multiplier could be applied to both the acceleration and braking force in game, keeping everything else the same. 10% might do the trick, perhaps a little more. I don't think a huge change is needed, despite the discrepancy I noticed in acceleration times.

    Then once the train performance is sorted out, perhaps DTG can work out how to turn on the interior lights and how to get passengers to leave the train when it reaches the end of the journey. Finally, they can sort out the loo. I know it's unpleasant for track workers, (and players walking the line - perhaps that's why they've locked the loos out of use), but it's a long way from Manchester to Leeds and I'm getting rather desperate.
     
    Last edited: Jan 26, 2020
    • Like Like x 9
  2. Tonto62

    Tonto62 Well-Known Member

    Joined:
    Dec 2, 2019
    Messages:
    416
    Likes Received:
    728
    It's my favourite train to drive in TSW. It has it's faults but overall, it's very impressive. The timings on the Trans Pennine route are tight to say the least. Have you tried the Tees Valley? It has much more achievable timings and is my most driven route. I hope Dovetail haven't finished making routes for the 101, I'd gladly buy anything which includes it, it's so rewarding and realistic to drive.
     
    • Like Like x 1
  3. Anthony Pecoraro

    Anthony Pecoraro Well-Known Member

    Joined:
    Dec 11, 2016
    Messages:
    3,175
    Likes Received:
    3,806
    You can turn on the passenger lights. There is a switch to the right of the handbrake.
     
  4. Trim

    Trim Active Member

    Joined:
    Jan 24, 2020
    Messages:
    143
    Likes Received:
    188
    Tees Valley is on sale right now and I am very tempted to buy it.

    As I said earlier, the timings in NTP match the prototype so they ought to be achievable. In the 80s of course there weren't any timekeeping targtets. but I very much doubt five-minute late arrivals were the norm at Manchester Victoria and Leeds.

    When I drive, I do turn on the lights. But why don't AI drivers turn them on? It's dark in those tunnels.

    Of course, there are other isssues with the lights, at least at night. Passengers' faces look grim and the window reflections are virtually non-existant (which I suppose is a good thing otherwise we'd need to close the screen behind the driver when driving at night, which unfortunately seems to be stuck).
     
    Last edited: Jan 26, 2020
  5. Tonto62

    Tonto62 Well-Known Member

    Joined:
    Dec 2, 2019
    Messages:
    416
    Likes Received:
    728
    If you enjoy the 101, definitely buy the Tees Valley, you'll love it. Plenty of interesting freight activity too and scenery that varies from urban to rural to heavy industrial. Plus it has working AWS. The class 31 add on is worth getting too.
     
  6. Trim

    Trim Active Member

    Joined:
    Jan 24, 2020
    Messages:
    143
    Likes Received:
    188
    Quoted from another thread, but I think replying here makes more sense:
    Since the game's power twin cannot keep time, I wouldn't have thought there was any chance of the 3-car DMU doing so. However I've done some testing and it seems the TVL 3-car unit has much the same performance as an NTP power twin - for the results, see here:
    https://docs.google.com/spreadsheets/d/1-EZifkaqGO0XYlM7jLM9lKB59F_jXYh7lx_ONZzJ_Qw/edit?usp=sharing

    Since I needed to find equivalent bits of track on both routes, I used Standedge Tunnel for the NTP testing, being the longest piece of level track. Does anyone know if TSW adds extra drag in tunnels? I wouldn't have thought it would make much difference with double track. The braking performance was a little better on NTP, which suggests it might be from extra drag, although the differences are only a couple of seconds, which could be down to my faulty measurement. At least my braking results appear to be validated in one respect: longer trains take longer to stop, which ought to be correct, because it takes longer to vent the vacuum.

    Back to the prototype, I'm now searching my memory for whether three car sets were used, but I was only an infrequent visitor to the Diggle line (as it was then usually known), and I really cannot remember. Certainly Neville Hill had a remarkably large number of power twins, which were virtually unknown in most parts of the country.

    Incidentally, I see the Wikipedia page for the class 110 Calder Valley units has some performance test results. I'll maybe see if I can do some equivalent tests with the NTP 101; my guess is a 3-car 110 ought not to be much different from a power twin 101; the 110s had significantly more powerful engines.
     
    Last edited: Jan 27, 2020
    • Like Like x 2
  7. 749006

    749006 Well-Known Member

    Joined:
    Dec 10, 2016
    Messages:
    5,243
    Likes Received:
    1,546
    The local timetable is wrong as in BR days the service was split at Huddersfield with very few through workings.
    The 110s lived to their name as Calder Valley units and normally ran via Hebden Bridge instead of Diggle.
    From my days driving Class 101s around Manchester there did not seem to be that much difference in the braking capacity of a two or four car set. The Brakes on a 4 car did release quicker as each engine had a Vacuum Exhauster.
    I don't know if the files could be modified to allow the three car 101 on the Diggle Route

    Peter
     
    • Like Like x 2
  8. Anthony Pecoraro

    Anthony Pecoraro Well-Known Member

    Joined:
    Dec 11, 2016
    Messages:
    3,175
    Likes Received:
    3,806
    Diggle route?
     
  9. Manclion

    Manclion Well-Known Member

    Joined:
    Sep 20, 2018
    Messages:
    224
    Likes Received:
    485
    Diggle junction via Huddersfield.
     
    • Like Like x 1
  10. Tonto62

    Tonto62 Well-Known Member

    Joined:
    Dec 2, 2019
    Messages:
    416
    Likes Received:
    728
    Diggle station was situated immediately after emerging from Standedge tunnel westbound. It had four platforms I think as there were two single bore tunnels as well as the double bore one used in the game. My dad got stuck there in snow, in the winter of 1947 I think it was. He was on duty for 24 hours. There's no trace of the station but the old tunnels appear in the game.
     
  11. Manclion

    Manclion Well-Known Member

    Joined:
    Sep 20, 2018
    Messages:
    224
    Likes Received:
    485
    The old station building is still there immediately after the viaduct approaching Huddersfield but is represented in game by a bog standard house asset.
     
  12. Tonto62

    Tonto62 Well-Known Member

    Joined:
    Dec 2, 2019
    Messages:
    416
    Likes Received:
    728
    I thought that was the remains of Saddleworth station. Diggle station was literally just before Standedge tunnel. A bit like Morley, out of the tunnel, straight into the platform.
     
  13. Tonto62

    Tonto62 Well-Known Member

    Joined:
    Dec 2, 2019
    Messages:
    416
    Likes Received:
    728
    • Like Like x 2
  14. Manclion

    Manclion Well-Known Member

    Joined:
    Sep 20, 2018
    Messages:
    224
    Likes Received:
    485
    • Like Like x 1
  15. Trim

    Trim Active Member

    Joined:
    Jan 24, 2020
    Messages:
    143
    Likes Received:
    188
    You sent me scurrying away to look up a braking circuit diagram. Of course, DMUs had a separate reservoir pipe throughout the train, something I have never had experience of. As I recall, the game doesn't model this, but I'll check it out tonight.

    For anyone interested, there is an excellent article on vacuum brakes here:
    http://www.railway-technical.com/tr...x-l/train-equipment/brakes/vacuum-brakes.html
     
    • Like Like x 2
  16. DominusEdwardius

    DominusEdwardius Active Member

    Joined:
    Dec 8, 2016
    Messages:
    167
    Likes Received:
    198
    It does model the release pipe on the 101, that's what the right gauge needle is! And also why if you repeatedly apply and release the brake you can run out of high side vacuum so you're stuck with the incredibly slow vacuum exhauster's (which are dependent on engine speed so you can speed them up by revving the engines up).
     
    • Like Like x 3
  17. Trim

    Trim Active Member

    Joined:
    Jan 24, 2020
    Messages:
    143
    Likes Received:
    188
    All vacuum brake systems have a high vacuum system, but usually this isn't connected down the train - there is just one vacuum pipe between vehicles - so all the brake release vacuum has to be provided by the leading locomotive. As Peter pointed out in post #7, DMUs are different in that there is a vacuum release pipe connected throughout the train, which allows all the high vacuum reservoirs and exhausters throughout the train to help release the brakes.

    As far I am aware, in the pre-DMU days of steam locomotives and auto-trailers (driving trailers), the driver in the auto-trailer had to signal (by bells) to the fireman to release the brakes because, although the driver had a brake valve and could apply the brakes, there wasn't a vacuum release pipe connected through the train so the brakes could only be released from the locomotive. That must have been fun!
     
  18. DominusEdwardius

    DominusEdwardius Active Member

    Joined:
    Dec 8, 2016
    Messages:
    167
    Likes Received:
    198
    All automatic vacuum brakes have a chamber or reservoir side depending on how it is arranged but that isn't used for the release of the brake, nor is it piped, its the thing which creates the pressure difference in the brake cylinder allowing the brake to apply, in normal service that just remains stuck at 21"Hg (or 25"Hg if you're GWR) unless you pull the brake release strings or they leak off in which case the brake will release.

    So when you apply the brake that remains stuck at 21"Hg and the trainpipe side falls to whatever say 10"Hg giving you 11"Hg of pressure difference, granted due to compression in the chamber side, friction and weight of the brake rigging it'll probably be more 8"Hg of pressure difference acting on the brake rigging.

    The high side release pipe is specific for first gen DMUs and is an entirely separate system allowing you to use a higher vacuum stored in a reservoir (typically around 28-9"Hg) to quickly draw the brake off to work around the slow release of the engine driven exhauster. That is what is exactly modelled in TSW.
     
  19. Trim

    Trim Active Member

    Joined:
    Jan 24, 2020
    Messages:
    143
    Likes Received:
    188
    Since the trains I used to work on also had a high vecuum reservoir, and twin vacuum gauges (but the high vacuum side was not piped through to other vehicles, even other locomotives), I assumed this was standard. I would have hated to have relied just on the exhauster to release the brakes; they were pretty feeble things, and took ages to charge the high vacuum circuit when preparing the locomotive.
     
  20. hyperlord

    hyperlord Well-Known Member

    Joined:
    May 20, 2019
    Messages:
    807
    Likes Received:
    765
    God I become so grumpy when I even think about the 101 - I'm too stupid and left all of those rides aside, shame, I know.
     

Share This Page