The 803 has been able to move under its own power for many years but with issues. The last few months a 600 v compressor was installed inside and that allows a good supply of air for controls and braking. In this form she first ran maybe ten days ago, and after further testing pulled many trains this last weekend.
Kudos to all who made the Labor Day weekend possible! Moving so many people and pieces of equipment simultaneously is an achievement to be proud of. I've been to the Museum many times and have not seen so much activity at any one time. THANKS to all who made it happen.
It was great to see the 803 out of the barn. I rode the caboose train behind it on one of the few runs it made in the morning of Labor Day. The 803 pulls very smoothly.
It appears that running the 803 is a bit of a workout since the pantograph has to be raised and lowered numerous times to avoid problems with the trolley wire. The engineer has to get halfway out his window to check clearances, so he is in and out of his seat quite a few times. Thanks to the guys who pilot the 803!
I also learned something watching the 803 get ready to work. The 803 was parked on station track 2 overnight. Apparently all the air bled out of the engine overnight, so the engineer couldn't raise the pantograph pneumatically. Under the engine's body is a long tube that contains a long wooden pole. The pole is removed and the engineer can use the hooked end to raise the pantograph up to the wire by hand. As soon as the pantograph contacts the wire, the compressor starts and within a couple minutes, there was enough air to hold the pantograph to the wire. I would have never thought of that.
It was really nice to see a lot of equipment out of the barns and in the sunshine. Labor day was a great day to be a member!
I do not think so. Most traction motors are rated for a maximum of 750 volts so in the case of the 803 I am thinking that even in the maximum running point on the controller, two motors are permanently wired in series so as not to exceed the ratings. Current to the motors is routed first through a bank of resistors to drop the starting voltage to the motors. At our lower trolley voltage the ratio of that drop remains constant, sort of a voltage divider. The unit will operate without exceeding current ratings depending on the load applied. Less voltage to the motors, and a constant motor resistance equals less current to the motors. It will develop less horsepower and have less total rated load to pull a train. It will never reach the same speeds as on 1500 volts. This is a simplistic explanation and perhaps one of the electrical gurus will add to this or correct me.
The Joes were designed for 3000V but I'm fairly certain there has never been a 3000V motor. But there are 1500V motors (insulated for 3000V) and surely by the early 50's that's what they would have used, with the wiring arranged so that at maximum you still have them wired in pairs. South Shore would have rewired them so that at maximum they are singly across the 1500V. Running on 600V everything will just run slower with less power for a given controller position.
I know from old literature that when the IC suburban electrification was being planned, both Westinghouse and GE offered them 1500V motors but they opted to be conservative and go with series pairs of 750V motor (insulated for 1500V from ground).