AC traction vs. DC traction: Do railroads have to worry about its application?

Well a RR does not _have_ to worry about how AC traction locos are used but since AC locos cost more than DC locos it would be in the RR's best financial interest to use the AC's in service where the extra capital spent on the AC drive is producing higher productivity. And using an AC loco as a yard or industry switcher is NOT the most productive use of an AC loco.
As for new purpose-built switchers, these have always been bare-bones equipment. Things such as smaller prime movers because low speed dragging of cuts does not require high HP. Mechanically driven radiator fans instead of electric radiator fans and no traction motor blowers eliminated a companion alternator. So don't look for a RR to spend the extra bucks for an AC switcher. Today's new switchers are usually powered by multiple palletized small engine-generator sets that are cheaper and more fuel efficient than an AC road loco. And if a switch job requires more than that or a RR does not want to spend precious capital on new switch engines.. well there are a lot of 'paid-for' older DC locos out there to do the job.

I don't know the loading characteristics of post 2009 AC road locos but I had to use an SD70MAC several times on my yard engine job and it was a royal pain in the azz. 
Not to mention these big road locos are not permitted on many industry tracks account of light rail or tight curves and clearances.

Wyhog posted:

Well a RR does not _have_ to worry about how AC traction locos are used but since AC locos cost more than DC locos it would be in the RR's best financial interest to use the AC's in service where the extra capital spent on the AC drive is producing higher productivity. And using an AC loco as a yard or industry switcher is NOT the most productive use of an AC loco.
As for new purpose-built switchers, these have always been bare-bones equipment. Things such as smaller prime movers because low speed dragging of cuts does not require high HP. Mechanically driven radiator fans instead of electric radiator fans and no traction motor blowers eliminated a companion alternator. So don't look for a RR to spend the extra bucks for an AC switcher. Today's new switchers are usually powered by multiple palletized small engine-generator sets that are cheaper and more fuel efficient than an AC road loco. And if a switch job requires more than that or a RR does not want to spend precious capital on new switch engines.. well there are a lot of 'paid-for' older DC locos out there to do the job.

I don't know the loading characteristics of post 2009 AC road locos but I had to use an SD70MAC several times on my yard engine job and it was a royal pain in the azz. 
Not to mention these big road locos are not permitted on many industry tracks account of light rail or tight curves and clearances.

https://en.wikipedia.org/wiki/EMD_MP15AC

I know EMD made a MP15AC and 246 where built.  What advantage did they have for the railroads that bought them to spend extra for a diesel switcher with AC traction?

FECguy posted:

Wyhog posted:

Well a RR does not _have_ to worry about how AC traction locos are used but since AC locos cost more than DC locos it would be in the RR's best financial interest to use the AC's in service where the extra capital spent on the AC drive is producing higher productivity. And using an AC loco as a yard or industry switcher is NOT the most productive use of an AC loco.
As for new purpose-built switchers, these have always been bare-bones equipment. Things such as smaller prime movers because low speed dragging of cuts does not require high HP. Mechanically driven radiator fans instead of electric radiator fans and no traction motor blowers eliminated a companion alternator. So don't look for a RR to spend the extra bucks for an AC switcher. Today's new switchers are usually powered by multiple palletized small engine-generator sets that are cheaper and more fuel efficient than an AC road loco. And if a switch job requires more than that or a RR does not want to spend precious capital on new switch engines.. well there are a lot of 'paid-for' older DC locos out there to do the job.

I don't know the loading characteristics of post 2009 AC road locos but I had to use an SD70MAC several times on my yard engine job and it was a royal pain in the azz. 
Not to mention these big road locos are not permitted on many industry tracks account of light rail or tight curves and clearances.

https://en.wikipedia.org/wiki/EMD_MP15AC

I know EMD made a MP15AC and 246 where built.  What advantage did they have for the railroads that bought them to spend extra for a diesel switcher with AC traction?

Well Mr. FECguy, you might want to conduct a bit more research into just what an EMD MP15AC model REALLY is!  The MP15AC was NOT "AC Traction", i.e. it did NOT have AC three phase induction traction motors. The "AC" designation in the model "MP15AC" only meant that it was equipped with an AC alternator (Main Generator) and thus did NOT have the "old fashioned" D32 DC Main Generator.