[Traindude]

In modern push-pull commuter service, cab cars are placed on one end of a consist so as to remotely control a conventional locomotive or locomotives pushing on the other end of the consist. In spite of the fact that the car has a control cab, the car itself is not self-propelled. It must be MUed to the locomotive(s) in order to operate. It does, however, have a functioning horn, bell, headlight, and windshield wiper to provide protection for the train when the cab car is leading.

I'm here to ask if this is something that is worth implementing in OR (Click this link to vote on it). Essentally it's a passenger car with its own stand-alone cabview, horn, bell, headlight, windshield wiper, possibly even a speedometer, brake gauges and a vigilance alarm, but that's it--the car is not otherwise capable of propelling itself, and controls such as the throttle, reverser and brake handles actually control regular locomotives elsewhere in the consist.

I hope I got my facts straight there.

[ebnertra000]

That can be done already. In fact, ever since day one of MSTS, it's been possible. All you have to do is make the cabcar an engine and give it almost no power (0.01 of all power figures) and then set up the cab, sounds, etc.

[Traindude]

ebnertra000, on 20 August 2017 - 05:50 PM, said:

That can be done already. In fact, ever since day one of MSTS, it's been possible. All you have to do is make the cabcar an engine and give it almost no power (0.01 of all power figures) and then set up the cab, sounds, etc.

Does it still control the loco's at the rear?

[ebnertra000]

Yes, otherwise you'd ever get anywhere since the cabcar "engine" has so little power it could hardly move itself

[Traindude]

ebnertra000, on 20 August 2017 - 08:14 PM, said:

Yes, otherwise you'd ever get anywhere since the cabcar "engine" has so little power it could hardly move itself

Excellent!

I think I just wasted a Trello post there...

[eric from trainsim]

Yep. You did. ;)

It's assumed that all locomotives in a train are MU'd to whatever unit is in control, and each will contribute their own power based on the lead's throttle.

A speeder or handcar MU'd to a SD70ace will indeed go 75 mph uphill at 80% throttle.

[roeter]

eolesen, on 21 August 2017 - 10:09 AM, said:

Yep. You did. ;)

Well, I wouldn't be so harsh.
Allthough it does work by creating a driving trailer (cab control car or whatever name you is used) as an engine, it is not quite the same as having an actual car.
One of the problems is that a car is ofcourse much lighter than an engine, or even as a motor trailer as in MU's, making the unit much more prone to wheelslip. Some consists where power is 'shared' between engine and control car really do suffer from this problem. For some, for me as yet unclear reason, this is particularly the case for AI trains, which is one of the reasons it is not possible to fully rely on actual power for AI train control.

Personally, I would indeed welcome the prospect of 'real' control cars rather than semi-engines as required now. It would be a more realistic setup, in particular for MU configurations (MU as in 'fixed' Multiple Units (EMU or DMU) as used in Europe, not as in Multiple Unit control as used in USA).

Regards,
Rob Roeterdink

[darwins]

roeter, on 21 August 2017 - 02:43 PM, said:

Personally, I would indeed welcome the prospect of 'real' control cars rather than semi-engines as required now. It would be a more realistic setup, in particular for MU configurations (MU as in 'fixed' Multiple Units (EMU or DMU) as used in Europe, not as in Multiple Unit control as used in USA).

Regards,
Rob Roeterdink

Dare I ask if there is if there is progress currently planned towards this?

I have just placed a card in the Trello road map requesting consideration of this. (Push-Pull, Pull&Push, Motor train, Auto train, Driving trailer..) It really does need a separate category. With modern diesel and electric some driving trailers can work with any loco that has the right MU gear. With these and with multiple unit trains the 'power' dials in the cab - ammeter, wheel-slip need to give information about the (nearest) power unit.

It is even more difficult with steam. I am not at all happy with the MSTS work arounds and OR does not seem to like it if you set the steam loco parameters too small. (Plus of course if you have a boiler pressure gauge it should give you a readout for the loco that is doing the work.

Has anyone so far found an Open Rails work around for steam trains that they are reasonably happy with?

[darwins]

Some more playing with these things.
I have just found that a diesel unit driving trailer will function with zero power - in this case it seems to require gearbox entry, brake controllers entry and cab controls, but happily works without any diesel engine.
Engine ( Class101_DTCL_E56050_BRBf

Wagon ( Class101_DTCL_E56050_BRBf )
Type ( Diesel ) Comment (* OR does not support Driving Trailer *)

Comment (********** Gearbox *************)

DieselEngineType ( mechanical )

GearBoxNumberOfGears( 4 )
GearBoxDirectDriveGear( 4 )
GearBoxMaxSpeedForGears( 15.3 27 41 65.5 )
GearBoxMaxTractiveForceForGears(29200N 16500N 10700N 7150N )
GearBoxOverspeedPercentageForFailure( 106 )
GearBoxOperation( manual )
GearBoxEngineBraking( direct_drive )

Comment (*************************** Brake System *********************************************
Included in this section - Compressor, Reservoir, Application rates, etc
**************************************************************************************)

Comment (*** Braking systems ***)
BrakesTrainBrakeType( vacuum_single_pipe )
ORTSBrakeServiceTimeFactor ( 80 )
ORTSBrakePipeTimeFactor ( 0.01 )
TrainPipeLeakRate ( 0.04 )

Comment (*** Exhausters ***)
ORTSBrakePipeChargingRate ( 0.64 )
Comment (* ORTSBrakePipeChargingRate Assumes rapid charging from reservoir pipe *)
Comment (* Mechanical exhausters - depend upon engine speed - charge vacuum reservoir - twin pipe system - not modelled in OR *)
Comment (* Unit fitted with quick release twin pipe vacuum brake system - brakes section should be updated if this becomes functional in Open Rails *)


Comment (*** Brake Valve Combined ***)
TrainBrakesControllerMaxReleaseRate ( 2 )
TrainBrakesControllerMaxApplicationRate( 1 )
TrainBrakesControllerMaxSystemPressure ( 21inHg )


Comment (************************** Engine Controls **********************************************
Included in this section - Controllers for Regulator, Reverser, Brakes, etc
*****************************************************************************************)
The only problem with that being that the tachometer always reads zero, whereas on the real thing it would give the speed of the engines in the motorised car!
So perhaps we are closer to having working driving trailers for diesel than we thought.

[darwins]

Following the above I have also now spent some time looking at driving trailers for electric multiple units. The same method can be used for driving trailers that are propelled by any diesel or electric locomotive that does not have gears.
In general these vehicles can be specified as having no power. OR does give an error message where no powered axles are specified in the Engine part of the file

Type ( Electric )
NumWheels ( 0 ) Comment ( * 0 axles powered * )
However this does not seem to impact on functionality and I suspect it is probably better to leave the number of driving axles as zero in the hope that in future OR will accept this as normal for driving trailers, which might be specified as
Type ( DrivingTrailer )
NumWheels ( 0 ) Comment ( * 0 axles powered * )
There needs to be a complete set of entries in the braking section and in the engine controllers section.
This means that any vehicle with a driving cab must have an eng file to allow the engine controllers to work.
In addition to that all motor cars, including non-driving motor cars in electric multiple unit trains must have eng files (not wag files) so as the correct physics or power, tractive effort and potential for slipping can be modelled.
Non-driving motor cars must have number of driving wheels, adhesive mass, power and tractive effort specified. They do not need to have an engine controllers section and most do not require brake data to be included in the engine part of the file.
The exception to this is for vehicles that have dynamic or blended braking. For these a full set of brake information must be included in the engine section.
So there work around to having driving trailers or commuter cab cars for modern traction is both fairly simple and very effective.
At some point soon I will see what can be done with push pull trains or auto trains propelled by steam locomotives. I suspect that the easy work around for this might be to define the driving vehicle as being Type ( Electric ) or Type ( Diesel ) rather than Type ( Steam ).