New Member/Train handling questions

[M Train Via Loop]

Hey, All -

This is my first post on these forums, though I've been a regular reader for several years now. I've found a lot of great information from some very reliable and first-hand sources, and I appreciate everyone - current and past railroad and rapid transit employees and those interested in trains, railroad and transit operations and history - who takes the time to share their insight, knowledge and experiences with other members and guests.

The M-2 retirement thread had me think about these questions, which may have been answered in other threads (sorry if they were!). Regarding dead cars in a consist:

1.) What is the percentage necessary to take a train out of service, and is it weather condition-dependent?

2.) How are trains with frozen electrical equipment repaired/serviced and placed back into service? Is it as simple as thawing and drying out the gear?

3.) Do dead cars affect slip-slide conditions, i.e., air brake lock-up, the loss of electronics regulating slip-slide control, etc.? Does the loss of the dynamics ever lead to flat spots on the wheels in slick conditions?

4.) I've spoken to a few engineers on the NHL, and they seem to prefer the M-2's over the M-4's and M-6's from an operating standpoint. Are their noticeable differences in the way that the different equipment handles?

Thanks!

[Clean Cab]

We can't answer most of your questions, but I'll try to answer a couple.

"Dead Cars" use only air brakes and it has no afftect when the train is in "slip/slide" and it can evetually lead to either wheel shelling or flat spots.

As to differences bewteen the M2, M4 and M6, I personally prefer either an ATC modified M2 (either CSR or Morrison-Knudeson second phase rebuild) or an M6. Almost everyone HATES the M4s as it require maximum braking to comply with a cab signal downgrade that is much harsher than an unmodified M2.

[M Train Via Loop]

As to differences bewteen the M2, M4 and M6, I personally prefer either an ATC modified M2 (either CSR or Morrison-Knudeson second phase rebuild) or an M6. Almost everyone HATES the M4s as it require maximum braking to comply with a cab signal downgrade that is much harsher than an unmodified M2.

Thanks for your response.

I thought that all NHL EMU's had Schedule 26 GRB-1 brake systems. Why do the M4's require more braking effort?

[RearOfSignal]

I thought that all NHL EMU's had Schedule 26 GRB-1 brake systems. Why do the M4's require more braking effort?

Because...

Almost everyone HATES the M4s as it require maximum braking to comply with a cab signal downgrade that is much harsher than an unmodified M2.

When the cab signal drops the engineer has to acknowledge the downgrade and apply the brakes sufficiently to satisfy the ATC system; the M4's require more braking effort to do so.

1.) What is the percentage necessary to take a train out of service, and is it weather condition-dependent?

2.) How are trains with frozen electrical equipment repaired/serviced and placed back into service? Is it as simple as thawing and drying out the gear?

1) I don't think there's a real percentage, as Clean Cab said most of the M2 fleet has some sort of fault(dead cars, dynamics etc.) so there just has to be effort working cars to get the train over the road. And if the equipment did have a serious problem instead of taking the whole train(or consist) out of service they could swap out the problematic pair, or triplet at the nearest yard. But as was said before there isn't a whole bunch of well working equipment just laying around the yard to replace them with. Especially at this time of year. A common saying around here is "if it rolls it goes."

2) Well water has a tendency to short things out, so even if it's dried there still might be damage done to certain components.

[Clean Cab]

It's not that the brakes on M4s are any less effective than the M2's or M6's. It's that you must keep the brakes on a bit longer to satisfy a cab signal downgrade on an M4. That's just the way they were designed.

[gmbfly98]

It's not that the brakes on M4s are any less effective than the M2's or M6's. It's that you must keep the brakes on a bit longer to satisfy a cab signal downgrade on an M4. That's just the way they were designed.

So a software design "feature", then?

[DutchRailnut]

No pure hardware, the M4 ATC has no software.