Reportedly, Norfolk Southern started a trend of operating together units of the same type. Union Pacific seems to have adopted that philosophy too. Below is an SD70M and two fellow mates heading east on the Sunset Route in Pomona, CA, plus a dead switch engine on Friday, June 30, 2017.
(Click on photos to see full version.)
What was fascinating about the three same types of units was that ALL had new wheel sets!
These units are 15 or more years old! With new wheel sets on multiple old units, is UP giving the units an element of immortality? Will these SD70M type units still be heading mainliners 15 years from now? Will those then 30 year old units receive new wheel sets too? How long do wheels last anyway?
K.P. has heard the SD70M cabs creek on the road.&nbs
Reportedly, Norfolk Southern started a trend of operating together units of the same type. Union Pacific seems to have adopted that philosophy too. Below is an SD70M and two fellow mates heading east on the Sunset Route in Pomona, CA, plus a dead switch engine on Friday, June 30, 2017.
(Click on photos to see full version.)
What was fascinating about the three same types of units was that ALL had new wheel sets!
These units are 15 or more years old! With new wheel sets on multiple old units, is UP giving the units an element of immortality? Will these SD70M type units still be heading mainliners 15 years from now? Will those then 30 year old units receive new wheel sets too? How long do wheels last anyway?
I don’t see why wheel replacement would be considered surprising. I see dozens of Wheel/Traction motor sets sitting outside the Roseville shops lined up for the GE’s and the various EMDs. They get swapped all the time. Further, the only reason the 70Ms are getting more work in matched sets is that the SD60s have been bumped off of the shorter trains with the 70Ms taking over. So you’ll see 70Ms and 59MX for power on these out of West Colton and Roseville. And of course, I see 70Ms on trains going up and down the hill, up and down the valley, up to oregon, over Feather River. Mixed in with GEs and 70ACes. All day every day. Some of the oldest were being stored for a while, but that time has been over for months now.
Uh, they’re SD70s?!? so they of course have 16-710 Turbocharged engine and DC Traction motors. There are a couple different phases of the SD70M represented in the UP roster, but they’re all Turbocharged 710s and DC traction.
Precisely. I don’t think many realize just how often locomotives get servicing on their wheels. It’s actually pretty regular to have them turned on essentially a lathe to be perfectly round again. Eventually, the wheels run out of “tread” and need to be replaced wholesale.
Wheels in each truck tend to wear somewhat uniformly, so it isn’t all that surprising that they’re all replaced at the same time.
As has been mentioned, this is routine maintenance.
As far as running together, when you have 1400 of them, that’s going to happen. Seeing as they’re the mainstream of UP’s Direct Current traction fleet, it is even less surprising, since they’re not going to mix AC and DC quite as much because they’re each best at different tasks. The big ACs go on the coal, intermodal, and drags while the SD70Ms take care of the lighter stuff and heavy locals, generally speaking, just the same as you’d assign a GP40-2 to the yard, not coal service.
Actually, that’s not particularly true at all. While I have not ever seen an SD70M on a coal train. That’s about the only service I’ve not seen it on coming through Roseville. They are in service on every conceivable train from stack trains to forest products to monster drags bookended by AC units of all types. UP don’t care.
Wheels generally last for 400K to 600K miles on SD70’s before they must be replaced. They will be trued 3-5 times during their life to restore the tread/flange profile. The common causes of wheels needing truing is: 1) thin flange, 2) high flange, or 3) flat spots. With the HTCR radial steering truck on these locomotives, high flange is typically the reason for truing. A new flange is 1" high relative to the tread, when the wheel tread wears so that the flange is 1.5" high, it has to be trued. New wheels are either 42" or 43" diameter depending on what the RR chooses, the wheels can wear to 39" at which point the rim thickness is at it’s condemning limit. Smaller than that, the gearcase would also be less than the FRA minimum allowable of 2.5" above the rail.
Obviously they’re going to mix…a lot. I was going after the more general preferences, than a clear-cut definition. Given three ES44ACs and three SD70Ms, consisted into those sets, and one intermodal train and another manifest drag, they’re probably going to put the GEs on the stacker and the EMDs on the drag.
It’s a hugely general statement, but one which shows how each type of locomotive tends to be best suited to certain tasks, so the railroad try to keep them on those tasks.
Much more segregated than UP is BNSF, who runs the SD70s almost exclusively on coal trains.
The real question regarding the SD70s, especially for UP is when they will be replaced. Remember the record setting 2000 unit lease order that at the time saved EMD? Another 2K unit order to EMD would re-establish in the market place and keep GE honest in pricing.
My guess it’ll be a long time before the SD70M are replaced since UP’s still using 35-40 year old SD40-2 that have been recently rebuilt for continued service.
IMO, I think there could be the NS-style option of rebuilding or remanufacturing UP’s SD70M’s too, especially if EMD or a rebuilder figures out how to incorporate AC-traction into a SD70M even though, unlike GE’s Dash 9s, SD70Ms don’t share the same frame with their SD70MAC AC counterpart. BNSF are NS are both rebuilding some of their Dash 9 fleets to AC traction and it’s not out of the possbility that such an option will be offered for the SD70 series.
BNSF has SD70MACs that run on Coal trains almost exclusivly. the SD75M fleet runs system wide when they are in use.
And no, UP would not make that distinction on an Intermodal vs. manifest. Unless it was one of the big supersized manifests heading over the hill that NEED AC. If it’s a normal Forest Products train to Oregon, then they put on whatever. This is based on my conversation with the people building the power sets in Roseville.
That the rebuild of an EMD locomotive from DC to AC is possible is indicated by comparing the export version of the SD70ACe, the GT46C-ACe with its most recent version called the GT46C-ACe Gen II.
The older version had the two inverter cabinets, one in front of the engine and one at the rear, like the SD70MAC layout.
The “gen II” has only one inverter cabinet, about the same size as that required for control of one truck, which provides individual axle control.
At least one of these GT46C ACe Gen II units has been built at Muncie and has been tested.
The original GT46C ACe only just fitted on a frame 22 metres over couplers and had a particularly compact dynamic brake unit with twin fans side by side since a single fan of adequate capacity wouldn’t fit and the frame was filled end to end.
The Gen II version with one less inverter cabinet will have a walkway at the rear since there is now no need to use the whole frame.
I’d say that the current EMD individual motor control inverters would fit in the space of the DC switchgear on an SD70M and wouldn’t require the long frame of the SD70MAC.
I’d expect that older SD70MACs might get rebuilt first, since they could use the existing motors, just replacing the old inverters as they become unsupportable.
