Discussion related to commuter rail and rapid transit operations in the Chicago area including the South Shore Line, Metra Rail, and Chicago Transit Authority.

Moderators: metraRI, JamesT4

  by MetraF40C607
 
Well, I heard it would overcharge the trains, and the whole thing would be screwed up. Donno, not sure. Just what I believe.

  by Tadman
 
So these MP's don't even have AC traction motors? Wow that's rough, because AC motors and invertors are perfect for stop/go like commuter- which is why South Shore and (i think) CTA has them...

  by c604.
 
"because AC motors and invertors are perfect for stop/go like commuter"

Why are AC motors better for commuter service?

  by F40CFan
 
The CTA is considering AC traction for its next equipment order.

  by MikeF
 
It is a little surprising that the MP36's were built with DC motors. My guess is Metra didn't want to deal with a small fleet of locomotives with a different propulsion system -- the same reason the new engines were built with 645 prime movers. They probably also saved a boatload of money by going with DC.

AC propulsion is better in general, not just in commuter service applications. The motors are simpler in design than DC motors and are thus more reliable and easier to maintain. They are also less susceptible to overheating. The drawback to AC propulsion is that it requires additional expensive electronics, namely a solid-state inverter and a phase control module, to drive the AC motors. But, greater flexibility and control are possible, resulting in better performance overall. Anyone who rode the South Shore cars before they were rebuilt with AC motors can attest to the greater performance of the AC propulsion.

  by AMTK84
 
Ah.
Last edited by AMTK84 on Mon Apr 11, 2005 4:58 pm, edited 1 time in total.

  by MetraF40C607
 
No Mike, I don't believe I caught that very OBVIOUS hint you gave me.

  by Tadman
 
I've heard chatter about noise levels of MP's being high, but I confirmed it last friday - The CUS exit to Madison street has a mezzanine at engine roof level, and standing that close to an F40 wasn't as loud as ground level by an MP - the MP puts out way more bass too.


Also, a comment about AC traction being discussed above - MikeF is quite right that invertor control and AC motors are expensive - I deal with that stuff every day in the electric crane world, but it also prolongs the live of the motors, gearboxes, and any other mechanical and electrical components on the locomotive (or in my case, crane).

  by F40CFan
 
Tadman wrote:I've heard chatter about noise levels of MP's being high, but I confirmed it last friday - The CUS exit to Madison street has a mezzanine at engine roof level, and standing that close to an F40 wasn't as loud as ground level by an MP - the MP puts out way more bass too.
Thank You.

  by AmtrakFan
 
There have been problems with them on the BN the crews hate them.

  by JamesT4
 
I got a idea since the only lines that dont have them is the UP. I say that once UP finish their bridge works,Metra should let the UP get some of the MP's and see how the UP drivers react to them.


The BN, and some metra employees hate them, so lets see if the UP employees like or hate them.