Class 165 balancing speeds (per notch)

IamSparticus · 22 Oct 2019

Hello all ... my first posting and I searched about but couldn't see any similar posts.

Class 165 DMUs have 7 traction lever notch positions. Is there any rule of thumb as to the balancing speed for each notch ?.

I appreciate gradient, wind speed, and many other factors affect achieved speed but would appreciate at least ballpark figures.

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hwl · 22 Oct 2019

IamSparticus said:
Hello all ... my first posting and I searched about but couldn't see any similar posts.

Class 165 DMUs have 7 traction lever notch positions. Is there any rule of thumb as to the balancing speed for each notch ?.

I appreciate gradient, wind speed, and many other factors affect achieved speed but would appreciate at least ballpark figures.

75mph or 90mph versions?

HLE · 22 Oct 2019

As with a lot of units this will also vary between units within the same class.

For balancing I assume you mean holding speed? This to a degree will be down to driving style

IamSparticus · 23 Oct 2019

Apologies for the poor posting earlier
- 75 mph
- yes holding speed.

Although the class can be configured with up to 12 carriages, My need is just for the smaller 2- and 3- carriage trains.

Kurolus Rex · 23 Oct 2019

IamSparticus said:
Apologies for the poor posting earlier
- 75 mph
- yes holding speed.

Although the class can be configured with up to 12 carriages, My need is just for the smaller 2- and 3- carriage trains.

A driver will typically go between two notch settings to maintain a speed. They will normally use a lower notch to shave off a few mph once they reach their desired speed and then use a higher notch to accelerate back up to the speed again. Is this what you mean by "balencing" ?

Formation length wouldn't make any difference when it comes to speed etc since they're DMUs and each coach powers itself (unless there's something i'm missing here).

I'm not a driver so i'm not sure what notches are required for each speed etc. It does vary massively as others have noted depending on the gradient.

May i ask why you want to know this? It will be easier to help you if we know what you want this information for.

Llama · 23 Oct 2019

If be surprised if anyone can give an answer to this question. It's not something that gets tested on a windless, gradient-less, passenger-less day on clear signals on straight track with all the time in the world. Too many variables.

II · 23 Oct 2019

I believe the turbocharger kicks in at notch 5. For a GWR unit on level track you'll get to 90mph in 7 or 6, and might just about eventually get there in 5. Notch 4 and you'll struggle to get much above 60, and progressively lower through to notch 1 where you're probably looking at about 30mph after a long wait. As 'Llama' says, there's a huge variety of conditions and variations within the fleet that means only very rough estimates can be given.

Llama · 23 Oct 2019

If some of the 165s have the same Perkins 2006-TWH engine as some 158s do, the turbo will always be operating but its effectiveness will increase as engine revs increase. There's a big increase between power notches 4 and 5, I haven't seen the figures for a Perkins engine (only the Cummins equivalents) but I'd guess that the power output %age for each notch on one of our Perkins 158s would be something like:
Notch 1 - 5%
2 - 10%
3 - 15%
4 - 20%
5 - 50%
6 - 75%
7 - 100%

IamSparticus · 25 Oct 2019

Thankyou all for you help and especially the Perkins 158 data as that's a good starting point for me. I was hoping the relationship between notches would not be linear.

I'm building up a dynamic model to run in Train Sim of the Class 165s taking into account train mass, rolling resistance, drag, gradient, rail head condition, etc.

Kurolus Rex · 25 Oct 2019

IamSparticus said:
Thankyou all for you help and especially the Perkins 158 data as that's a good starting point for me. I was hoping the relationship between notches would not be linear.

I'm building up a dynamic model to run in Train Sim of the Class 165s taking into account train mass, rolling resistance, drag, gradient, rail head condition, etc.

Ah, good luck to you then! The Class 166 that we have is attrocious (particularly the physics, worst i've ever seen), it's good to see that there might be hope.

hwl · 25 Oct 2019

Llama said:
If some of the 165s have the same Perkins 2006-TWH engine as some 158s do, the turbo will always be operating but its effectiveness will increase as engine revs increase. There's a big increase between power notches 4 and 5, I haven't seen the figures for a Perkins engine (only the Cummins equivalents) but I'd guess that the power output %age for each notch on one of our Perkins 158s would be something like:
Notch 1 - 5%
2 - 10%
3 - 15%
4 - 20%
5 - 50%
6 - 75%
7 - 100%

The actual Notch setting data:

1 8%
2 17%
3 41%
4 56%
5 68%
6 82%
7 100%

The 165 come in 2 flavors 75mph (Chiltern) and 90mph (GWR) with the same hydraulic transmission unit set up for both but different final drive gearbox ratios. The internal gear ratios in the Voith T211 and the final drive gear ratios are different from the 158 with Perkins so different physics from the 158...

Llama · 25 Oct 2019

Those figures suspiciously exactly match the figures for units with Cummins NT855R5 series engines, I suspect that they're not the ones for Perkins 2006-TWH, certainly not the 158s with those engines (I've never driven 165s so am not sure about those but if they have the same air-actuated fuel rack and seven power notches I would suspect they're the same as 158s).

On a Perkins engined 158 there's no way there's such a small jump from power notch 4 to 5, they barely move in notch 4 but in 5 they take off.

hwl · 25 Oct 2019

Llama said:
Those figures suspiciously exactly match the figures for units with Cummins NT855R5 series engines, I suspect that they're not the ones for Perkins 2006-TWH, certainly not the 158s with those engines (I've never driven 165s so am not sure about those but if they have the same air-actuated fuel rack and seven power notches I would suspect they're the same as 158s).

On a Perkins engined 158 there's no way there's such a small jump from power notch 4 to 5, they barely move in notch 4 but in 5 they take off.

Transmission efficiency is quite noticeable different between N4 and N5 which makes the difference seem bigger.

computerSaysNo · 25 Oct 2019

Kurolus Rex said:
Formation length wouldn't make any difference when it comes to speed etc since they're DMUs and each coach powers itself (unless there's something i'm missing here).

For a 2 carriage train at speed there would only be 2 engines (assuming one engine per carriage) to push against X amount of air resistance onto the front of the unit, for e.g. a 10 carriage train, there would be 10 engines pushing against almost the same resistance. Would this alone have much effect on performance?

Kurolus Rex · 25 Oct 2019

GregA said:
For a 2 carriage train at speed there would only be 2 engines (assuming one engine per carriage) to push against X amount of air resistance onto the front of the unit, for e.g. a 10 carriage train, there would be 10 engines pushing against almost the same resistance. Would this alone have much effect on performance?

I don't believe so no, though i'm happy to be corrected.

On a MU (Multiple Unit) each coach is powered by it's own engine. It isn't reliant on any other coaches to push or pull it, since all the engines are producing the same amount of power.

In contrast, unpowered coaches (Mk4s, Mk3s etc) are not able to provide their own traction and instead are reliant on an external source (a locomotive) to push or pull them. That's additional weight that the loco needs to push or pull, so train length does effect performance here.

Again, that's just my understanding, and i'm no physicist. Happy to be corrected!

hwl · 25 Oct 2019

Kurolus Rex said:
I don't believe so no, though i'm happy to be corrected.

On a MU (Multiple Unit) each coach is powered by it's own engine. It isn't reliant on any other coaches to push or pull it, since all the engines are producing the same amount of power.

In contrast, unpowered coaches (Mk4s, Mk3s etc) are not able to provide their own traction and instead are reliant on an external source (a locomotive) to push or pull them. That's additional weight that the loco needs to push or pull, so train length does effect performance here.

Again, that's just my understanding, and i'm no physicist. Happy to be corrected!

The first vehicle always has higher aerodynamic loadings than the following vehicles especially as the speed increases so on MUs the rest effectively end up pushing the first slightly.

158747 · 25 Oct 2019

GregA said:
For a 2 carriage train at speed there would only be 2 engines (assuming one engine per carriage) to push against X amount of air resistance onto the front of the unit, for e.g. a 10 carriage train, there would be 10 engines pushing against almost the same resistance. Would this alone have much effect on performance?

It does make a slight difference, for example a 3-car 158 will climb a gradient a few MPH faster than a 2-car unit.

Kurolus Rex · 25 Oct 2019

hwl said:
The first vehicle always has higher aerodynamic loadings than the following vehicles especially as the speed increases so on MUs the rest effectively end up pushing the first slightly.

I was thinking this too after i posted that. In theory, since the carriages are coupled together, the force would travel down the length of the train and could eventually be overcome by the forces pushing in the opposite direction, pushing the carriages towards the front a little. Does this have any effect on performance or are the forces too minute?

hwl · 25 Oct 2019

158747 said:
It does make a slight difference, for example a 3-car 158 will climb a gradient a few MPH faster than a 2-car unit.

A 2 vs 3 car 195 is 20-25 seconds difference to get to 100mph with similar differences for doubling up units vs not.

HLE · 25 Oct 2019

A little, yes. A 2 car 153 always pulled off a little quicker with 2 than on its own, in my experience. Brakes didn't seem to stick on as much either.

Class 165 balancing speeds (per notch)

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