Driving the BR101 in HHL it seemed like the AFB was more aggressive (and late) in responding to speed limits compared to before in HRR. For example while leaving Hamburg and just going up to 40 km/h in about 150-200 kN of power, the AFB would actually reduce power so late it had to use electric brake. This didn't occur in HRR and I think that the gradient at Hamburg Hbf is relatively flat (if it was descending steeply then the "old" BR101 would of course go into E-brake immediately upon reaching 40 km/h). Am I imagining things?
I would have thought it has to do with the fact that you are commanding two 101s, as it is a sandwich configuration, hence double the power.
Ordinarily in passenger consists set up top-and-tail the trailing loco is being pulled dead, since there's really no need for it until the train reverses direction. Passenger trains just aren't all that heavy. Besides, I don't think German locomotives are set up for DP operation. (This doesn't apply to quasi-DMUs/EMUs like the Class 43 or ICE2, which were designed to operate as a pair of locos in a permanent trainset)
Works the same way as it does with a cab car. Whether you control the trailing loco from another 101 or from a cab car makes no difference. All of the 101 sandwiches I could find on YouTube had both 101s powered up. Some examples:
Despite, what ever happens in reality does not mean it’s not happening in TSW. In TSW I would think that both locos are powering your train. If you try the 101 sandwich scenario on HRR you do feel it. Acceleration is faster, hardly any slip and you also notice it when using electric brakes, they feel “double as strong”. wanted to add something on how it is handled IRL usually. What Lamplight says is correct, German locos are very capable of DP. And if you have a sandwich they are usually both powering. As long as you see a panto up it’s powered. And if you see the front panto up on a leading loco it usually means that there is a trailing loco under power as well. You can even mix certain classes in a sandwich, ie 101 and 120 could power the same train. And a 120 could not be pulled dead, as it would otherwise be limited to 140kmh, hence you had to power both of them if you wanted to stick to your schedule. Of course, no rule without exceptions
I think you have to turn on the ZDS multiple traction switch at the back of the cab for the rear locomotive to contribute. I'm pretty sure I never enabled this function since I didn't think to check whether there were two locomotives in the consist. I can't double check the behavior of the AFB on HHL at the moment since I refunded the DLC but (if anyone is interested) it should be quite easy to check: Set the AFB target speed to something like 40 km/h or 50 km/h and then apply a fixed amount of power (maybe 50 kN/FM) on similar consists in both HHL and HRR and see whether the AFB overshoots on HHL. Also, if you enable doppeltraktion you should (I think) be able to notice whether the AFB is of P-controller (proportional control, control input is proportional to error between reference and output/current value) type or PD/PID-control (extra terms proportional to time derivative of error (D), i.e. fast things are changing and the integral of the error (I) i.e. it remembers how "wrong" it has been) since a P-controller will be worse at handling the extra power than PD/PID. I suspect that BR101 has some form of PD/PID since it is quite good at handling grades etc while the BR185.2 is probably a simple P-controller since it usually gets stuck around 10-5km/h below target. Although I could be wrong since it's been a few years since I took control theory in university.
I am pretty sure that the double traction is set up with the timetable. I don’t think you have to do anything to enable this in this instance, as all locos are already powered up (sort of). However, I might be completely wrong… can’t check HHL either, as I, too, opted to get it refunded until some stuff is fixed…
The service mod for HMA has push-pull config. I'll test and report back. EDIT: So, I just tested accelerating up to 30 km/h with both the multiple locomotive selector in ZMS and ZWS and off and there was no difference in the time to reach 30 km/h. I remember Maik (either in mail correspondence or on the Rail-sim.de forums) stating that certain locomotives (I think it was the BR185.2) would limit the max amperage/max tractive effort in multiple traction so maybe you don't accelerate faster in dry conditions, only in low adhesion conditions where the added number of axles will improve your overall traction. Maybe Maik Goltz can answer this?
