Lickey incline - A challenge !

[Minilad]

Right. In the words of Jigsaw. Let's play a game

I'm sure you are all aware of the formidable Lickey Incline on the main Birmingham to Cheltenham route. Well how do you think a train performs going up it ?

Today I have driven a Class 170/5 unit up the bank on a Cardiff to Nottingham service. Two cars both powering. A dry rail and good conditions. Train reasonably loaded with around 110 people on board. At the bottom of the bank passing through Bromsgrove station I was doing line speed, bang on 80mph, power controller wide open all the way up.
So the question is. What speed do you think I was doing upon cresting the summit ?

The whole internetz to the closest figure.
Good luck

 

[Lampshade]

I'm guessing with the abysmal power:weight of a 170... 35mph?

 

[Hydro]

30. Aren't the 170's pretty gutless?

 

[The Planner]

27 or 28 at a guess.

 

[Minilad]

Some interesting guesses so far. Have to shoot off to Nottingham in a bit so can't really give any clues at this stage. But when I finish I will see where everyone stands and maybe give a few pointers !!

 

[Blindtraveler]

27 or 28 at a guess.

when did it last year on a moderately loaded 3 car, it was 25ish according to the guard who was quizzed about the slow running by another passenger. Out of interest, how does it compare to the steaper bits of the highland mainline? The scotrail 170s, whilst admittedly rammed much of the time toil and usually have cooling fans running most of the trip. On the odd time you get a 158, it performs much better and seams to keep time.

 

[asylumxl]

0. Everyone got out and pushed.

 

[Blindtraveler]

0. Everyone got out and pushed.

lol!

 

[CarterUSM]

36mph.

 

[87019Chris]

15mph

 

[trainfanatic]

I'd hazard a guess and say 45mph (well, the wind is blowing south to north!!)

 

[Rugd1022]

Fastest I've ever gone over the top with a 66 and 1,700 ton in tow is 22mph!

I'm guessing 35mph for your unit

 

[Captain Chaos]

23mph

 

[MCR247]

22mph

 

[317666]

19mph

 

[Nym]

47mph

 

[asylumxl]

On a more serious note than my previous post, assuming linear deceleration going up the incline and no wheel slip what so ever, 31.3mph or so.

 

[Xenophon PCDGS]

29.8 mph

 

[sprinterguy]

I'd wager that it'd be faster than the 170s on the LM Hereford to New Street runs that make a stop at Bromsgrove at the base of the bank. Man they really crawl up there...at least the Cardiff to Nottinghams' get a good run up!

If it's not taken already, I'll hazard a guess at 41mph.

 

[clagmonster]

You're asking for a reason, so I reckon it was either a particualrly good or particularly bad unit. 14mph.

 

[Minilad]

You're asking for a reason, so I reckon it was either a particualrly good or particularly bad unit. 14mph.

No reason really. Just thought I would give everyone a little something to think about. Unit was pretty average. Not really good or bad

Most people seem to be doing my little 170 a disservice !! But there have been a few close guesses so far and one very very good guess !!

 

[Eng274]

While 170s are underpowered, they are pretty heavy buggers, and with 110 passengers and full power applied, that would give it a decent amount of momentum going up the incline - I'll say 56mph.

I am inclined (ha-ha) to defend the 170 as well, despite being a bit slow off the mark they are reliable trains. I wouldn't want to be too close to the coolant filler cap when it's opened after a hard day's service though.

 

[Nym]

Could one bring some science to the party and actually work out what it should be, it would be a hell of a calculation to do and proberbly wrong because physics rearly works in the real world, and goodness knows where in the power curve the engines would have been sat.

 

[Eng274]

Could one bring some science to the party and actually work out what it should be, it would be a hell of a calculation to do and proberbly wrong because physics rearly works in the real world, and goodness knows where in the power curve the engines would have been sat.

I've dug out my 1st year dynamics notes to try and solve this, but as you say it is not a constant deceleration up the hill due to the dropping revs giving a varied power level. Since I do not have a power curve chart to hand for the MTU engine a few assumptions may have to be made.

 

[Blindtraveler]

oh and whether my guess was wrong or not appologies to XC Driver for slagging his 170 - most rood of me and unforgivable given the other multiple unit he signs.

 

[tonytrainsfree]

the max train speed is 100 mph so it wall be going up the incline between 43mph and 50mph

 

[asylumxl]

Could one bring some science to the party and actually work out what it should be, it would be a hell of a calculation to do and proberbly wrong because physics rearly works in the real world, and goodness knows where in the power curve the engines would have been sat.

Well we can't find that so I just worked it out assuming it was deaccelerating in a linear fashion. Most you can do really.

XCDriver should just put us out our misery!

 

[Minilad]

OK OK here goes. Congratulations to trainfanatic and honourable mention to Nym
The speed at the top was 45.5 MPH
Compare that to a 220/1 that would go over at no less than 65 with all engines, and sometimes the line speed of 75

 

[Eng274]

OK OK here goes. Congratulations to trainfanatic and honourable mention to Nym
The speed at the top was 45.5 MPH
Compare that to a 220/1 that would go over at no less than 65 with all engines, and sometimes the line speed of 75

Seems a fairly reasonable speed for a 170.

I wasn't able to get a sensible answer for the final speed, I did find out reasonable figures for some other variables (with 110 passengers weighing average 60kg, the whole train weighed exactly 100t ), and I found this on Voith's website, which confirms that this was a far more complex problem than a simple linear calculation. The chart on page 2 shows that the train would probably have slowed down to 45mph, at that point the tractive force of the engines would balance against the resistance caused by the incline.
I could not realise a suitable friction coefficient, for steel-on-steel; many different sources threw up a wild range of answers ranging from 0.05 to 0.78

A very interesting challenge, XCDriver

 

[Nym]

Didn't I say 46 or 47?

Nice... It's not too bad to be honest...