UP SD70MAC and flaired SD70M

[WestSlopeRRfan]

RE: UP SD70MAC and flaired SD70M

and BNSF runs ton's of sd70's (and sd60's as helpers) on that subdivision. I guess the decision has to do with tonnage and required train speed.

BNSF likes to use the SD70M's on coal trains. They use the Dash 9's for freight service. If you look at UP its the exact opposite. Although you see more variety in UP's freight service. From what I learned at this site and others, along the tripple track Powder River Basin if BNSF and UP trains are side-by-side the UP train will win ALWAYS. The GE's which feature the AC technolgy perform better on the heavy trains. BNSF is slowly learning this (BNSF just placed a big GE order).

Nick

[jlucero4]

RE: UP SD70MAC and flaired SD70M

Just a couple more notes on this subject. The main way to tell the difference between an SD70MAC and an unfalired SD70M is by the length. A SD70MAC is approximately 3 feet longer than an SD70M. The extra legnth is needed to house all the AC traction equipment.

BTW, I personally like the look of an unflaired SD70M myself. I think the unflaired units look more streamlined, plus the flairs make the engine look too much like a G.E.

Jordan L.

http://home.earthlink.net/~bnsfjordan

[plainsman]

RE: UP SD70MAC and flaired SD70M

Just to correct something, the BNSF locomotives are SD70Macs not SD70Ms. This is a little confusing, but the SD70M is a DC locomotive, used in high speed freight service, the SD70Mac is the AC version used on the coal trains.
Bob

[Chessie System]

RE: UP SD70MAC and flaired SD70M

so....the MAC part of the SD70 is a SD70m with AC traction motors...and a SD70M has a DC motor

[cnw8717]

RE: UP SD70MAC and flaired SD70M

Actually the M in MAC stands for Modified North American Cab. And AC stands for AC Traction motors.

cnw8717

[BN_9402]

RE: UP SD70MAC and flaired SD70M

BNSF has three variations of the EMD 4000HP units, the SD70MAC, SD75M, and the SD75I.

The GE ACs are far better in performance but lack in durability and the shop guys hate GEs. The EMDs have, as of lately, found there way into maintainance and regular manifest work. BNSF will be receiving three GE EVO units before the end of the year and the next order of GE ACs will be the new AC45s, much like the ones that UP is currently testing in Northern California.

Austin
Midwest Rail Group

[WestSlopeRRfan]

RE: UP SD70MAC and flaired SD70M

Thanks for the clarification. Now it makes sense.

Nick