 |
Re: Chicago METRA to get Passenger version SD70MACs
Author: J
Date: 02-22-2019 - 13:13
Max Wyss Wrote:
-------------------------------------------------------
> But removing traction motors would make things
> even worse. "Commuter rail" operation needs high
> tractive force or decent acceleration,
> particularly with such a high non-productive
> weight.
Don't disagree but METRA used 6-axle locomotive for close to 30 years. See the following image. F40C
At the time these were constructed I recall they were a compromise - similar to Amtrak's SDP40F's they could be repurposed as freight locomotives if needed. In fact Santa Fe did just that with a few of them.
In the case of changing the center axles to idlers on these SD70's, my weak understanding of electrical engineering is that the remaining 4 AC traction motors can absorb all the output from the main alternator. While these locomotives may not be optimal, the price may be attractive enough to be a compromise. And no need for nostalgia - I recall the handsome Ae6/6's in service too.
-------------------------------------------------------
> But removing traction motors would make things
> even worse. "Commuter rail" operation needs high
> tractive force or decent acceleration,
> particularly with such a high non-productive
> weight.
Don't disagree but METRA used 6-axle locomotive for close to 30 years. See the following image. F40C
At the time these were constructed I recall they were a compromise - similar to Amtrak's SDP40F's they could be repurposed as freight locomotives if needed. In fact Santa Fe did just that with a few of them.
In the case of changing the center axles to idlers on these SD70's, my weak understanding of electrical engineering is that the remaining 4 AC traction motors can absorb all the output from the main alternator. While these locomotives may not be optimal, the price may be attractive enough to be a compromise. And no need for nostalgia - I recall the handsome Ae6/6's in service too.
