Trainwire [may I call you TW?],
I must have Northerns stuck in my head [AKA the "4-8-4" reference]. The BNSF - former ATSF has donated a Northern type to a Steamers club, and they run it on excursions for BNSF and public stuff at least once a year.
The stories told by the crews - both the crews of the steamer and the diesel which must accompany it - are compatable to being on board!
Let me see if I have the term correct on this Baldwin. Is this an Allegeny class 2-10-2, or was that an articulated 2-10-10-2?
Love to take my wife to UP's Nebraska shops, where they have the museum of motive power - mainly to see the still in use 4-6-6-4 Challenger.
Not sure if they have any of the 4-8-8-4 Big Boys, or any of the Gas Turbines. Ever been there???
BTW, I have some pictures of the most common Class 1 carriers in my area posted on the web. If you want to check them out, here's the URL:
http://www.railfan.net/railpix/scott/ As to the Traction Motors, the normal ampere load on the DC traction motors which would be drawn at low speed is in the 900 Amp range. This value is quoted in helper operations for starts on grades and with the slack bunched up. This would be at speeds between 5 and 12 MPH and with power throttle set at Run 6 from dead start [on sanded rail], ranging to Run 8 max.
If the load current drops below 900 A, the Engineer of the Helper set [Pushing, or DP near the end] can tell the grade which the leads are on has decreased, and back off the throttle. If the load exceeds 900 A, then the leads are taking on more grade, so it's time for more throttle.
AC traction motors can sit at stall [or speeds lower than 5.7 MPH] with higher currents and for longer times. This makes them an obvious asset for DP, Helper sets and similar tasks.
I recall the maximum of 900 Amps for DC Traction Motors used on "2nd Generation" units - such as EMD's Dash 2 series locos, or GE's Dash 7 locos as being the max continuous load current. Higher levels could be drawn for limited time [like 5 minutes]. I'll check into this and see what the books say [the books being both the Manuals and the Railroad's specs].
It was difficult to get high loads out of the "Bell Ringers" [GP 30s and GP 35s] since they would fault out so often - hence the term "Bell Ringer".
Love to talk Locomotives! I'll toss some other specs in here or in another thread.
Scott S.E.T.