Class 159 and 159/1 question

[nsupersonic]

Thinking about getting the payware soundpack for the 158/159 by Armstrong Powerhouse and was just curious about a recent real - life experience.
The sound on the payware pack sounds great, but has anyone pushed it to it's quoted maximum speed of 90mph; using the new sound pack.

Why I ask; is that I had was fortunate in real life- courtesy of South West Trains removing stops (very late train service) on the Salisbury via Basingstoke to Waterloo. This meant that the driver opened up the throttle all the way, this being on a new refurbished unit and had an obvious new Engine. The speed and acceleration was similar to the old express EMU sets, running Waterloo to Southampton non stop in the 1970's. You got the feeling it was in excess of 90mph.

Does anyone know whether the new refurbished 159/1 (by Wabtec) can go faster than their stated maximum speed of 90mph?

Present model in Railworks seems slightly underpowered and I was going to alter the maximum speed to reflect a real life 159 or 159/1

regards
Charles

[Kariban]

Maybe the refurb ones will do over 90 - given it's awful aerodynamics that must be pushing it - but I've had a couple of drivers tell me their 158s will struggle to get anywhere near that. Altering the max speed in the blueprint won't necessarily do anything at all - it's just a handy parameter to stop the train going any faster rather than telling it to go to that speed. I have just spent most of the week rewriting the 158 physics to match the transmission and some provided times, and it takes a good few mins to get up anywhere near 90 - although I don't actually have a proper cD figure, just some educated guesswork. I did find a report showing it shoves about twice as much air around ahead of itself as a 166, which is pretty terrible :p

IIRC the 159/1s still had the 350bhp engine?

And the RW one isn't underpowered at all. It's not way overpowered like the 166, but it's still too much, check the physics forum.

[nsupersonic]

Many thanks for that - some 159/1's did indeed have a 400hp engine fitted, the rest were 350hp - not sure how many..according to the guard when asked ...

Also trying some educated guess work on acceleration vs timimg using RW tools + simulated guess work travelling through Woking staion on the Portsmouth DLC

Regards
Charles

p.s - The refurbished 159/0 - on the outward journey did seem to be lacking the power of the 159/1 - just for info..
Also the 159/1, just seemed to have better acceleration - that may be down to good engine tuning at Salisbury depot

[Kariban]

I have a sneaky suspicion the 350bhp ones will accelerate better until they change to the direct drive, thanks to peak power being at higher RPM - output for a torque converter depends on input speed and the diameter of the whole thing, there's not really any fancy tricks like you can do with an electric system. Usually you'd match the transmission but we're talking late 80s BREL here, chances of that I suspect were pretty small. But then again just an overhauled engine can make a big difference to anything, those 159s do quite some mileage. I need to make a few trips on them sometime anyway, although down this end of the line they never really get going that much, too many hills & corners.

[Kromaatikse]

I do know that Pacers can get up to more than their rated 75mph. I've observed some very spirited (and perhaps unwisely so) running on the Newcastle-Carlisle line. But that is perhaps slightly less surprising since they are slightly "cleaner" than a 158 but have similar power/transmission units.

[thetrainfan]

I do know that Pacers can get up to more than their rated 75mph. I've observed some very spirited (and perhaps unwisely so) running on the Newcastle-Carlisle line. But that is perhaps slightly less surprising since they are slightly "cleaner" than a 158 but have similar power/transmission units.

The top speed on the Tyne Valley is 65mph?

[Kromaatikse]

Yeah, I did say it was unwise. Of course, the speed limit may have been different at the time, too.

[AndyUK]

I do know that Pacers can get up to more than their rated 75mph. I've observed some very spirited (and perhaps unwisely so) running on the Newcastle-Carlisle line. But that is perhaps slightly less surprising since they are slightly "cleaner" than a 158 but have similar power/transmission units.

Same transmission as far as I know but I don't think you can really call a 225 bhp Cummins 'L' series engine similar to a 350/400 bhp Cummins 'N' series unless you are comparing the number of cylinders or maker's name .

Andy L

[Kromaatikse]

Well, I suppose the smaller engine is compensated for by the lower gearing of the final drive (compared to the 158) and the smaller loading-gauge profile.

I'm not quite sure how I missed it being a smaller engine, though. Perhaps it's because it actually sounds louder inside a Pacer than inside a 158.

[holzroller]

Don't know if it is still the possible, but I had 158's over 90mph when running late in the 90's. There was a noticeable difference in acceleration if you had two sets together, more so with 3. Of course they are now 20 years old and I haven't driven one since 1996, so I don't know what they are capable of now. Areodynamically, though I have to say that they were streets ahead of the poor old 156, very noticeable in a strong headwind.

[alexnick]

A few years ago when I worked in a train planning department we debated this with the idea of 12-car 158s. We thought that 100mph would not be a problem for them and may well be reached by drivers looking to catch up on delays, with a possible maximum of between 105-110mph. Naturally it would take a long time to reach this, though we did decide that running units in multiple increased acceleration and speed: as the power to weight ratio remained unaltered, this shows the resistance value of air etc. (think of the trailing units as running in the first's slipstream).

I agree with the above posts about mechanical condition. If you read the preserved railway press, mainline steam throws up some brilliant examples of what is in theory a smaller less powerful engine outperforming a larger one - where class 7 rated 34067 and 5043 have frequently been thought to be outperforming class 8 pacifics, which comes down to quality of maintenance and restoration. The same would apply to all motive power therefore, and I did speak to an SWT traction inspector once who said that even members of the modern Desiro fleet develop individual characteristics.

The railworks problem goes back to mechanical/hydraulic transmission simulation, where in RW, the throttle position represents a maximum speed setting - so the RW model is limited to 90mph (falling gradients notwithstanding). If it were handled more in the way a diesel-electric transmission is, you would find that the throttle represented a power output, so on these DMUs it would be possible to exceed the stated maximum.

AN

[Kariban]

RW is a bit more sophisticated than that, it's just the DH model is a fixed tractive effort for each notch that doesn't seem to take any notice of speed, which is what a fluid coupling does - which is why I threw it out. Secondly the default one has it's "MaxSpeed" parameter set pretty low which is why it won't do over 90ish - if you balance the drag setting and the power properly, you don't need that at all. Finding the drag coefficient isn't the easiest thing in the world to do ... the other thing is to get loads of full throttle standing start-top speed timings and average something out, which also isn't the easiest unless you travel on them a lot and own a GPS ( or you drive them, anyone volunteering? ).

Slipstreaming is a well known phenomenon which I'm not sure RW deals with, I'll have to run tests on that. Technically it makes the front vehicle faster too by removing the drag-inducing turbulence behind it - it gets shoved to the rear of the train. It's possible to add some sort of train length constant multiplier into the physics I suppose.

Interesting comments though guys, keep 'em coming!

[bdy26]

Interesting thread guys. I recall a Railway practice and performance article in RM when the 158s came out - they got them over 100 on test on MML; I think that was a 4 car unit.

B

[Kariban]

Hm, RW does take something into account for multiple units, but it's a bit odd atm. Here's a graph for 0-90 ( on full throttle from start ) for my current 158, various length trains.



They all run out of puff at 91 mph, strangely, despite the acceleration. I suspect it might have something to do with my MaxSpeed figure being around 100mph, so I'll do it again later with that set to something impossible. The MaxSpeed entry just forcibly stops the train accelerating the nearer you get to the number, otherwise they tend not to stop accelerating ever, you just can't notice it after a while.

[nsupersonic]

max power increased from 350 to 400
max speed increased from 95 to 105

csv traction effort versus speed (graph - in rwtools) files altered - mainly guess work
managaed 95 with a lot of effort on a level track within my own WIP route

Charles