by JLJ061
I noticed on Metra Electric territory the line has periodic "Air Gaps" in the catenary and was wondering what they are for and how they are supposed to work?
Railroad Forums
Moderators: metraRI, JamesT4
JLJ061 wrote:What's really strange is I have seen South Shore motormen while running on Metra Electric actually be applying power to the traction motors while running through these gaps, which I thought was a no-no!The South Shore has not had motormen since the '60s; the guys you're referring to are engineers. While it's a good idea to shut off while running through section breakers, as it saves wear on the pan shoes and the wire hardware, it's not necessary. The modern MU cars draw plenty of current even when coasting so it doesn't really make a huge difference.
dinwitty wrote:boy, I hope the AC is in sync. MUed cars could stretch across the gaps.Isn't that the idea? Another poster here told me that FRA regulations forbid individual cars to be bussed together anymore - that is, each individual car is fed by its own pantograph or shoe. It's a good idea anyway, like you suggest, so a train of AC-powered MUs won't set off any fireworks when spanning electrical blocks of different phase, frequency, or voltage. As for the MU control signal, it shouldn't matter if it is in a different phase than the motor power supply.