SP5103 Wrote:
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> >Why can't a switcher operate on mainline
> trackage?
>
> They might have a gear ratio or truck design that
> limits their track speed. At 45 mph even on welded
> rail standard EMD switcher trucks ride like a
> bucking bronc.
>
> Most switchers are not equipped with toilets.
>
> Some railroads require leading units in road
> service to have dynamic brakes in grade
> territories, or may prohibit roots-blown EMDs in
> some fire prone territories.
>
>
> I think the statement being questioned was
> actually the opposite - without sufficient
> switchers or 4-axle units, six axle road units
> have to be used. I know UP is using pairs of
> SD40-2, SD60, SD60M, etc. on many locals where a
> pair of small units would have otherwise worked
> just fine. I also witnessed UP derail a six-axle
> for the second time on an industry track it had no
> business being on, evidently a second Geep wasn't
> available and the crew didn't want/think to split
> the power. UP by the late 1980s was already
> requiring all new industry spurs to be built with
> used 133# rail and be capable of being switched
> with any six-axle unit.
>
> The railroads would really like to have a one-size
> fits-all locomotive fleet. The days of assigned
> locomotive assignments to a division or pool are
> disappearing.

There is also the issue of alignment control couplers that are required for MU operation in some circumstances. Not sure if these UP units are equipped or not.