[darwins]

In theory the output from a torque converter drive looks like this:
https://i.imgur.com/MjFpmXF.jpg

The output from a three stage torque converter such as the Voith L630 or a four speed gearbox driving through a single stage torque converter such as the Mekydro transmission can be represented in OR by using tractive force curves.

The theoretical output from a mechanical gearbox looks like this:

https://i.imgur.com/NY54fZz.jpg

There is a representation of mechanical gears in OR that can be used to model a manual or automatic gearbox.

Many transmissions combine both a torque converter and mechanical gears. The theoretical output looks like this:

https://i.imgur.com/lfdubxS.jpg

Lindasyts has posted some data for a real example (The Voith T312r) here gearbox feature

I would like to get some more information about real transmission systems and their behaviour. If people have data they would like to share or links to information please post them here.

Some older systems names include Smith-Lysholm, Twin Disc, GM Allison and Rolls Royce as well as the various systems by Voith. (Possibly there might be published railway test data available in Germany about the Mekydro system and the various Voith systems.) Bringing things more up to date it would be interesting to know more about the ZF Ecomat gearbox and the Voith DIWA systems.

[darwins]

This is a very nice chart from Laci 1959

https://kephost.net/p/2022/14/5508_dd21bc61af36.png

It is for a diesel hydraulic transmission with two torque converter stages.
The two graphs are for different final drive gear ratios. (Gear ratio can only be changed when stationary.)

The nice thing about hydraulic transmissions is that they can be represented easily with tractive force curves.
This is for the low gear ratio:

DieselEngineType ( hydraulic )

Comment (* Tractive Force Curves for 2 stage transmission *)
Comment (* Shunting Gear Ratio *)

ORTSMaxTractiveForceCurves(
0 (   0 0	13.5 0  )

0.125 (
0.00	33600
0.81	11800
2.45	0  )

0.250 (
0.00	48600
1.55	16000
4.68	0  )

0.375 (
0.00	61000
2.26	20000
6.71	0  )

0.500 (
0.00	81000
2.98	25000
8.57	0  )

0.625 (
0.0	94000
3.29	28500
9.92	0  )

0.750 (
0.0	110000
3.73	32600
11.21	0  )

0.875 (
0.0	122000
3.92	37800
12.36	0  )

1.000(
0.0	139000
3.92	41200
13.39	0  ) )

...and this is for the higher gear ratio:

DieselEngineType ( hydraulic )

Comment (* Tractive Force Curves for 2 stage transmission *)
Comment (* Main Line Gear Ratio *)

ORTSMaxTractiveForceCurves(
0 (   0 0	27.0 0  )

0.125 (
0.00	16800
1.61	5900
4.90	0  )

0.250 (
0.00	24300
3.09	8000
9.35	0  )

0.375 (
0.00	30500
4.52	10000
13.42	0  )

0.500 (
0.00	40500
5.96	12500
17.14	0  )

0.625 (
0.0	47000
6.58	14250
19.84	0  )

0.750 (
0.0	55000
7.46	16300
22.42	0  )

0.875 (
0.0	61000
8.34	18900
24.72	0  )

1.000(
0.0	69500
9.40	20600
26.78	0  ) )

I have assumed the first two notches work the same as all the others. This may not be true. In some cases only one converter stage is used at low power or the changeover is locked to a fixed speed.

It is very easy to represent hydraulic transmission with advanced eng files - the challenge is how to do it in basic eng files!

[Laci1959]

ORTSMaxTractiveForceCurves (
	ORTSLowTorque (
0 ( 0 0 13,5 0 )               

0,125 (  
0,00 33600    
0,81 11800    
2,45 0
)      

0,250 ( 
0,00 48600    
1,55 16000    
4,68 0 )      

0,375 ( 
0,00 61000    
2,26 20000    
6,71 0 )      

0,500 ( 
0,00 81000    
2,98 25000    
8,57 0 )      

0,625 ( 
0,0 94000     
3,29 28500    
9,92 0 )      

0,750 ( 
0,0 110000     
3,73 32600    
11.21 0 )     

0,875 ( 
0,0 122000     
3,92 37800    
12,36 0 )     

1.000 (
0,0 139000     
3,92 41200    
13,39 0 ) )

ORTSHighTorque (    
0 ( 0 0 27,0 0 )               

0,125 ( 
0,00 16800    
1,61 5900    
4,90 0 )      

0,250 ( 
0,00 24300    
3,09 8000    
9,35 0 ​​)      

0,375 ( 
0,00 30500    
4,52 10000    
13,42 0 )     

0,500 ( 
0,00 40500    
5,96 12500    
17.14 0 )     

0,625 ( 
0,0 47000     
6,58 14250    
19,84 0 )     

0,750 ( 
0,0 55000     
7,46 16300    
22.42 0 )     

0,875 ( 
0,0 61000     
8.34 18900    
24,72 0 )     

1.000 (
0,0 69500     
9.40 20600    
26,78 0 ) ) )

Based on ORTSDieselEngines, I could imagine that. Instead of ORTSLowTorque, ORTSHighTorque any name is good, it can only be assigned to the torque converter. I intentionally did not use the name Gear, as opposed to the gearbox, because it can only be engaged when stationary.
But it could also be the other way around, as it is easier for Peter.

A Block Name (2
ORTSMaxTractiveForceCurves (
...
)
ORTSMaxTractiveForceCurves (
...
)

Of course, the ORTSMaxTractiveForceCurves blocks are linked to each stage from top to bottom.

[darwins]

At the moment I think it must be two different eng files. Whatever we call them, I think the idea of a "switch" between two different performance options might be what Serana is planning. http://www.elvastowe...post__p__278325

[Laci1959]

darwins, on 05 April 2022 - 08:10 AM, said:

At the moment I think it must be two different eng files. Whatever we call them, I think the idea of a "switch" between two different performance options might be what Serana is planning. http://www.elvastowe...post__p__278325

I thought it would be in a file.
The two separate eng files are already there because I have more of these locomotives. Half on a half-separated basis.
So that I create a task in which this driven vehicle and then, after loading, select the eng file that matches the task without exiting the task?
It's going to be a little weird, but I'll get used to it, users don't care. All you need to know is what gear to choose before you start moving.

[darwins]

I will be very happy when we can put different gear ratios, different brake timings, different voltages or even bi-mode power all into one eng file so that we do not have to exit the game or have multiple copies of the same engine.