I am interested with how the tap changer and notching system responds to a brake application and release when the notching lever is in the hold position. I understand about the power/brake switch on the train brake handle and how the rheo brake then kicks in and the tap changer is run down automatically. The bit in the game I would like some clarification on, is how when moving brakes back to running the system automatically taps back up to the notch you were in when initially applying the brakes if the notching lever is in the hold position (or above). Is this how the system was in real life, as I can't understand how that would work? Always like to expand my understanding and often someone on here has a good bit of info. cheers
Probably a long shot, but wondering if anyone had played this on Classic with the AP pack and if it exhibits the same behaviour?
I’m struggling to understand the scenario you’re describing. It sounds as if you’re talking about still having power applied when you start braking? If so that isn’t something you’d ever do. You should run the taps down fully before you start braking. If you don’t have time to do that, you should place the power controller into ‘Off’ which will cut off power instantly. The taps will continue to run down as you brake, and you won’t get regen braking. Then, when the taps reach zero, they will start increasing again to match your braking effort, bringing the regen brake in. When you release the brake the taps will return to zero, and only then can you start running the taps up again to get power.
Yes, that is what I am talking about, because the 87 had a special power brake switch apparently... Unique to the class 87, this locomotive is fitted with a power/brake switch on the train brake handle which means that as soon as you move the train brake handle away from ‘Running’, traction power is cut and approximately 500 amps of rheostatic brake is applied. Once the tap changer has completely notched down, normal rheostatic brake performance will resume.
So I did a bit more testing of this and certainly some slightly odd behaviour and the same happens on the 86 as well. It all depends on the sequence of inputs prior to breaking. If your last input prior to braking was a notch up and back to hold (using either method), then the tap changer will run back up to the previous notch position on brake release. Eg, you notch all the way up to 38 and hold then apply brake, return brake to running after the changer has notched down to 20, it will then notch back up to 38 with no input. But if your last input prior to braking was a notch down and back to hold (using either method), then the tap changer will remain on the notch it has run down to during braking when released. Eg, you notch all the way up to 38 and hold, then go down one notch to 37 and hold, then apply brake and return brake to running when changer has notched down to 20, it will remain at 20. Anyway, probably no one else cares, but that is what I found!!
