CHICAGO — Metra has taken delivery of another SD70MACH, part of an order of 15 of the remanufactured freight locomotives currently in progress for the commuter agency.
No. 505, the fourth in the series to arrive in Chicago, was delivered on Thursday, May 11. This unit is slated to have positive train control equipment added next week at Metra’s 47th Street Shops, the former Rock Island facility.
While the locomotives are the first six-axle power for Metra since the retirement of its F40Cs, these units will have four powered axles, operating in a B1-1B configuration. Four of the unit’s AC inverters will be used to drive the traction motors; one will provide head-end power for the passenger cars; and the sixth will serve as a spare. These will be Metra’s first AC-traction locomotives [see “Metra six-axle commuter locomotives,” Trains.com, Nov. 1, 2022].
A Metra spokesman said earlier this month that operational testing for the units was expected to begin in mid-May.
They still got to install PTC. This may sound dumb but METRA spent a lot of money rebuilding these locomotives. Don’t you think that they should have equipped the Locomotives with PTC and just tune it to the frequency they use.
Interesting that this rebuild has adopted GE’s (Wabtec) standard of one inverter for each axle rather than one inverter per truck. And the six-inverter package standard for a 6 axle loco yields a spare inverter since only 4 axles are motored. Wonder if the B1-1B arrangement gives any traction advantage over the A1A-A1A setup used on BNSF’s GE 6 axles?
I don’t think the arrangement was so much for traction but for a better distribution of weight. We have some local engineers here who could weigh in.
When it was announced these would service the UP based lines, I recalled that these lines have several weight restrictions which had disqualified the Motive Power MP36C buys,
Then someone reminded me that 4 axle power is quite enough but the weight distribution of the 6 axles help them deal with the weight restrictions.
EMD adopted the inverter per axle setup just over a decade ago when they switched to using Mitsubishi’s AC traction package..