If we ever find someone on this forum that isn’t a nerd, we kick them out. It’s never happened because everyone who likes games, simulators and trains is a fully paid up member of the nerds club, and we should all be proud of that.
It doesn't surprise me at all, haha ... But it looks crazy, Cane Creek! I know I know I know CRR now this can't sleep what to do?
My wife bought me one of those very chunky Steam gift cards for Christmas. Since I wasn't interested in the 2 high speed routes, it remained intact until Diesel Legends and Arosalinie. Now, I think there's just enough left for Clinchfield and perhaps one loco. Of course, my birthday is coming up........
Lovely! I got not very cheap (no at all) headphones. All the time I try not to think how many DLCs I would buy instead... I like them very much! (just in case)
To get back to the original topic... In the simulated version, it does nothing, but is interactive. In the real version, it's called a unit selector - BUT it doesn't do what almost everyone thinks it does. The commonly (and incorrectly) expected functionality of this switch is to select how many units provide power - i.e. if you have 4 units coupled, but set this to two, when you power up, only 2 will actually take power and the others will remain idle. On the F7, that's NOT what this does. It's actually a simplified description of a solution to a more complex electrical problem faced by these locomotives. First up - there is no "pin" on the cable which passes the unit selector value back, so there literally is no means of communicating this to the other locomotives. The "throttle" is managed via three pins on the MU cable (read up on "binary" to see how that works) and supports the 8 notches of the throttle. I.e. every loco in the MU set knows what the target throttle is by seeing what these pins are set to. This combined with the above, should confirm that every loco coupled to the MU set (with the big orange cable) will react to the same throttle setting by default. Dynamic brakes however are NOT a notched control, you can set them to any value between their minimum and maximum, and this is represented on the MU cable via a SINGLE pin which contains a variable voltage signal - think of it like dialling up the voltage to the track on your HO/OO set. As you increase your dynamic brake setting, so the voltage on this goes up, and this tells each loco in the MU set how much dynamic brake to apply. ... and here's where it goes wrong in reality... because in reality, by the time that voltage has made it back to the rear loco of a set, there's a good chance that it's reduced in voltage due to various reasons - wear on cabling, poor cabling, old cabling, joints that might not be perfect. So by the time your power signal on that pin has reached the rear loco, it will be a LOWER voltage than the one you set it to in the lead loco - which means the rear loco is applying LESS dynamic brakes than it should (and indeed, each loco back from the front will be applying a little less progressively more and more as you go away from the lead unit). What does the unit selector do then? It simply dials up the voltage which in turn brings up the dynamics on the trailing locos a bit higher than they were before. Why is it not simulated? We only figured all this out at the last minute so it was too late to put in - BUT - we also don't simulate any kind of electrical losses, so 10 volts in loco 1 is still 10 volts in loco 4, so in that case the switch actually would offer no benefits. It IS interactive, so you can set it to whatever you wish, the same as heaters etc are, but there is no change to the simulated behaviour as a result. Hope that explains it, apologies for forgetting to do so on the stream. Matt.
Thank you Matt for the explanation. I also thought it was the amount of units providing power. How do newer locomotives deal with the same problem? Or is it all dealt with with automatically by the locomotives?
