Union Pacific SD70M’s delivered in 2004 have two types of noses, the standard angled, pointed nose, and the non angled nose. (The last 13 units “delivered” of UP’s original 1000-unit order also had the treatment.) Why were there two types of noses?
(The two noses should not be confused with the very different, third type nose that EMD has on its current SD70ACe and SD70M-2 demonstrators.)
I believe the angled nose has to do with visibility reasons.
If it’s what I am thinking, it’s so the engineer can see the conductor riding on the front of the loco easier, as opposed to the non-angled nose whereby the hogger can’t see the front steps.
As well as improved visibility with the later SD70M nose design, the nose entry door is taller in the later nose design. This might be a result of new regulations. The “squarer” new design has fewer curves and is probably cheaper for EMD to build.