Excellent thread!

If memory serves me, the FL9s were rated at 1800 hp when operating in diesel mode. But what was the rating in electric mode drawing 600vdc off the third rail? While using this low voltage eliminated most of the on board power conversion equipment, I doubt they could develop full horsepower in electric mode. They probably didn't need to, as speeds in the electric area approaching Grand Central were not that high, nor that long.

A modern 4000 hp diesel retrofitted to pick up power off the catenary seems the ideal solution to many of the issues presented here. It would simply operate in electric mode whenever it could, and keep on truckin' in diesel mode where it couldn't.

That is - until you do the math! Picking high voltage AC off the catenary will require on board power conversion equipment. Oh you say - just stick it in some corner, or perhaps where the HEP power would go? But to develop the full 4000 hp, the locomotive would require at least a 3000 kw transformer and rectifier on board. Such devices take on huge proportions and undoubtedly will not fit unless you first remove the prime mover. -- thus no dual mode!

Using a lower voltage DC would offload the power conversion equipment. But merely move it to the wayside. And lots of it would be required every mile or so to avoid limiting horsepower. And worse yet, it would be idle most of the time!

It is this requirement for lots of wayside power conversion gear that causes most of the sky high costs associated with electrification. That is why most heavy electrifications in this country have been high voltage AC. According to a friend at CalTrain, their electrification study proposed a very high 25,000 volt system, minimizing the need for wayside substations, and thus eliminating much of the cost involved.

Perhaps, a good compromise would be to use an "Electrical Tender", which would pull very very high voltage off the catenary, convert it to match the existing prime mover output, then feed it to the diesels operating in slug mode when in electrified territory. The tenders could be kept in train the whole run or set out anywhere you please, making incremental construction immediately beneficial.

OPB