90 and 91's acceleration specific request!

[RichW1]

Hi all, now on 'Trouble On The Line' that I watched on youtube from the early 1990's it said and I quote 'The class 91 reaches 125mph at full power in just under 2 1/2 minutes'...yes it said two and a half minutes. I read today that class 90's reach their top speed '3 minutes faster than a 91'?????? Surely that's a typo or he missed the comma and meant to say reached its top speed in 3 minutes, not that the 90 reaches its top speed 3 minutes faster.

- Can someone of knowledge please tell me the technical details if they have them the acceleration from 0 - 125mph of a 91 and then 0 - 110mph of a class 90.

- Was the programme correct?

This debate has rumbled on and on, on and off for a ages and after seeing that programme, and if it was correct, has the performance deteriorated vastly or something?

 

[junglejames]

Dont know exact figures, but a 90 will reach 100mph before a 91 does.
Hopefully someone has more detailed figures.

 

[E&W Lucas]

It's a meaningless stat, as in reality the answer would be dependent on rail conditions, gradient and loading.

 

[es373]

Not to mention how ragged the things are now. Like all things it works pretty well when rolled off of the production line, but after 10+ years you wont get the same performance.

 

[junglejames]

It's a meaningless stat, as in reality the answer would be dependent on rail conditions, gradient and loading.

Obviously to make it fair, it would be based on perfect conditions on a flat stretch, both with the same load. Unfortunately, because perfect conditions are rarely encountered, its difficult to get exact figures.
All you can really say is that the 90s have better acceleration, but 91s have better top speed.

 

[captainbigun]

All you can really say is that the 90s have better acceleration, but 91s have better top speed.

That's not quite correct. All down to TE curves, line volts and a host of other things. 90s have better acceleration to about 65mph. 91s have had a number of modifications, and one of those is improved WSP performance, specifically the way that power is re-applied after a slip. So, infact, you may actually find that a 91 performs better across different track conditions as an average.

 

[notadriver]

Some performance logs I've seen in Railway Magazine suggest that a Class 91 set takes around 5 minutes to achieve 125 mph on level track with an HST taking around double that. I've also seen a quote that on departure from Milton Keynes a class 90 achieved 60 mph in 60 seconds but i've no idea what it was hauling. Class 90s hauling 10 coaches seem to have trouble maintaining top speed on 1 in 200 gradients of which there are many on the East Coast.

 

[dk1]

90s are great from a standing start when light engine. Great fun looking at peoples expression as you take flight with controller full open & doing your best to be enviromentally unfriendly

We did once do a test to time 0-100 light loco (even though it's 75mph max) but cannot remember what the result was.

 

[Aictos]

90s are great from a standing start when light engine. Great fun looking at peoples expression as you take flight with controller full open & doing your best to be enviromentally unfriendly

We did once do a test to time 0-100 light loco (even though it's 75mph max) but cannot remember what the result was.

That may be so but a Class 91 running light engine can still give a Class 90 also running light engine a run for it's money.

Having seen a 91 leave light engine, it's impressive how quick they move.

 

[captainbigun]

That may be so but a Class 91 running light engine can still give a Class 90 also running light engine a run for it's money.

Having seen a 91 leave light engine, it's impressive how quick they move.

That goes for any AC loco, you don't have to wait for the engine to wind up, the power is there instantaneously.

 

[brad465]

I've seen the acceleration on youtube for some class vehicles seen from the driver cab or by a portable device from the carriages of units. But, I cannot find anything on either of the two locos, or on other websites. :cry:

 

[thachieman350]

This shows the class 90's amazing acceleration

http://youtu.be/2eL6mnrmzXU

 

[brad465]

This shows the class 90's amazing acceleration

http://youtu.be/2eL6mnrmzXU

That is quick, however the loco had no load full stop, explaining why