Does anyone know the rough acceleration of the London Underground D78 Stock trains in m/s^2?

[BrTr]

I'm looking to find the acceleration and deceleration rates of the D78 Stock trains for something I'm working on, but can't seem to find anything helpful. Anyone able to help me out here?
The closest information I can find is that the S7 and S8 stock trains have superior acceleration to the D78 stock, and that their acceleration is 1.3 m/s^2, and that their acceleration is superior to Class 150s (cant find what the acceleration rate of 150s is either though...), so beyond that, I'm kinda lost.

Also, any tips on how I should find out the acceleration and deceleration of trains in the UK in general? Most trains don't have this info on their wikipedia pages, and it doesn't really seem like many people are really interested in this information.

 

[Samzino]

If I remember it was 1.0m/s^2 according to an old districtdave fourm thread. However that's before aero drag, friction, traction effort and Co start to reduce that.

 

[BrTr]

If I remember it was 1.0m/s^2 according to an old districtdave fourm thread. However that's before aero drag, friction, traction effort and Co start to reduce that.

I see, I imagine it'd be around 0.8 - 0.9m/s^2 with those factors included

 

[DelW]

I'm doubtful how meaningful a single figure would be. It would only be applicable on level track and with adequate adhesion, and the rate won't be linear other than within a limited speed range. That's before you get into variations between units and between drivers.

At best you might get a maximum value, but then even that could be exceeded when going down a gradient.

 

[edwin_m]

The value normally quoted is the acceleration at very low speed. At these speeds acceleration is limited by wheel-rail adhesion and the proportion of weight on motored wheels, but is nearly constant up to a certain speed because the speed-dependent factors of rolling and air resistance are pretty insignificant at low speeds.

Above that speed acceleration is limited by the amount of power available, and by the characteristics of the traction motors, so will reduce as speed increases further.

 

[D7666]

I'm looking to find the acceleration and deceleration rates of the D78 Stock trains for something I'm working on, but can't seem to find anything helpful. Anyone able to help me out here?
The closest information I can find is that the S7 and S8 stock trains have superior acceleration to the D78 stock, and that their acceleration is 1.3 m/s^2, and that their acceleration is superior to Class 150s (cant find what the acceleration rate of 150s is either though...), so beyond that, I'm kinda lost.

Also, any tips on how I should find out the acceleration and deceleration of trains in the UK in general? Most trains don't have this info on their wikipedia pages, and it doesn't really seem like many people are really interested in this information.

D78

acceleration rate

with 790 mm wheel, 111 m train length, 146300 kg train weight, EMPTY, 650 V line voltage, on level track :

0.63 m/s^2 0 to 5 km/h
0.98 m/s^2 from 5 to 30.0 km/h [series-parallel and full parallel] ***
1.09 m/s^2 30 to 32 km/h [WF1]
0.90 m/s^2 32 to 35 km/h [WF2]
then diminishes without any more notches from 35 km/h upwards e.g. 0.49 m/s^2 at 45 km/h, 0.29 at 55 km/h, 0.04 at 90 km/h

*** 0.98/0.99 rounds to 1.00 which is the commonly quoted value

& worse case

with worn 760 mm wheels, and 87313 kg passenger load, and 575 V line voltage (i.e. worst conditions) level track

0.58 m/s^2 0 to 5 km/h
0.99 m/s^2 from 5 to 22 km/h [series-parallel and full parallel] ***
1.09 m/s^2 22 to 25 km/h [WF1]
0.88 m/s^2 25 to 26 km/h [WF2]
then diminishes without any more notches from 26 km/h upwards e.g. 0.41 at 35, 0.21 at 45, 0.12 at 55, zero at 63.


Well, you did ask !


Brake rate 0.6 m/s^2 to 1.0 m/s^

 

[BrTr]

D78

acceleration rate

with 790 mm wheel, 111 m train length, 146300 kg train weight, EMPTY, 650 V line voltage, on level track :

0.63 m/s^2 0 to 5 km/h
0.98 m/s^2 from 5 to 30.0 km/h [series-parallel and full parallel] ***
1.09 m/s^2 30 to 32 km/h [WF1]
0.90 m/s^2 32 to 35 km/h [WF2]
then diminishes without any more notches from 35 km/h upwards e.g. 0.49 m/s^2 at 45 km/h, 0.29 at 55 km/h, 0.04 at 90 km/h

*** 0.98/0.99 rounds to 1.00 which is the commonly quoted value

& worse case

with worn 760 mm wheels, and 87313 kg passenger load, and 575 V line voltage (i.e. worst conditions) level track

0.58 m/s^2 0 to 5 km/h
0.99 m/s^2 from 5 to 22 km/h [series-parallel and full parallel] ***
1.09 m/s^2 22 to 25 km/h [WF1]
0.88 m/s^2 25 to 26 km/h [WF2]
then diminishes without any more notches from 26 km/h upwards e.g. 0.41 at 35, 0.21 at 45, 0.12 at 55, zero at 63.


Well, you did ask !


Brake rate 0.6 m/s^2 to 1.0 m/s^

that's actually very helpful, thank you!
Can I ask where you got the information from?

 

[D7666]

that's actually very helpful, thank you!
Can I ask where you got the information from?

You can ask but my answer is info is not in the public domain.

 

[notadriver]

I highly doubt a DC motored D78 train accelerates at 1ms/s^2 at any point on its acceleration curve.

 

[BrTr]

You can ask but my answer is info is not in the public domain.

right, but where did you get it from, are you an ex-rail worker of some kind?
Ah I see, well thanks anyways for the help!

 

[D7666]

I highly doubt a DC motored D78 train accelerates at 1ms/s^2 at any point on its acceleration curve.

Well you can highly doubt what you like.

right, but where did you get it from, are you an ex-rail worker of some kind?

Just accept the information and do not probe further.

This kind of questioning is why some do not post answers on these forums.

That applies to me now too.

Last time I post this sort of stuff in here for sure now.

 

[MikeWh]

right, but where did you get it from, are you an ex-rail worker of some kind?

You're new here, but that question really was a step too far.

Just accept the information and do not probe further.

This kind of questioning is why some do not post answers on these forums.

That applies to me now too.

Last time I post this sort of stuff in here for sure now.

I'm sorry that you've been pushed to this. Many members are very appreciative of the information provided by industry people. I hope you may reconsider in the future, but understand if you've been put off.

 

[BrTr]

Well you can highly doubt what you like.


Just accept the information and do not probe further.

This kind of questioning is why some do not post answers on these forums.

That applies to me now too.

Last time I post this sort of stuff in here for sure now.

I'm sorry, I did not consider how that question could come across. I did not mean to make you uncomfortable.

You're new here, but that question really was a step too far.

I'm sorry that you've been pushed to this. Many members are very appreciative of the information provided by industry people. I hope you may reconsider in the future, but understand if you've been put off.

I'm autistic, sometimes I don't see or consider other ways things I say can be interpreted.
To be clear, that's an explanation, not an excuse.
Sorry about my question, I've edited it now.

 

[Railperf]

D78

acceleration rate

with 790 mm wheel, 111 m train length, 146300 kg train weight, EMPTY, 650 V line voltage, on level track :

0.63 m/s^2 0 to 5 km/h
0.98 m/s^2 from 5 to 30.0 km/h [series-parallel and full parallel] ***
1.09 m/s^2 30 to 32 km/h [WF1]
0.90 m/s^2 32 to 35 km/h [WF2]
then diminishes without any more notches from 35 km/h upwards e.g. 0.49 m/s^2 at 45 km/h, 0.29 at 55 km/h, 0.04 at 90 km/h

*** 0.98/0.99 rounds to 1.00 which is the commonly quoted value

& worse case

with worn 760 mm wheels, and 87313 kg passenger load, and 575 V line voltage (i.e. worst conditions) level track

0.58 m/s^2 0 to 5 km/h
0.99 m/s^2 from 5 to 22 km/h [series-parallel and full parallel] ***
1.09 m/s^2 22 to 25 km/h [WF1]
0.88 m/s^2 25 to 26 km/h [WF2]
then diminishes without any more notches from 26 km/h upwards e.g. 0.41 at 35, 0.21 at 45, 0.12 at 55, zero at 63.


Well, you did ask !


Brake rate 0.6 m/s^2 to 1.0 m/s^

That just about sums up technically what I would explain from my journeys. They seem to pull away quite smartly up to about 25mph and then the acceleration rate starts to tail off quite noticeably. THi wasn't an issue in the central core with short distances between stations and low maximum speeds. But it did feel dreadfully slow on the longer open air sections out beyond Bromely By Bow.