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Slugs with motors
Author: Ernest H. Robl
Date: 12-05-2017 - 09:56
In a way, Gensets are slugs with motors. Under a light load, the extra diesel generator sets are basically ballast weight.
But, for a more direct example:
A number of years ago, I wrote an analytical article that offered a solution for a transition period if/when freight railroads ever decided to electrify. Though an acquaintance, who is a (now retired) professor of electrical engineering (with some interest in railroads), said the proposal made perfect sense, I could never get any magazine interested in publishing it.
Basically, this is the idea: You set up 3-piece motive power sets consisting of a six-axle diesel (using existing diesels), a new electric locomotive, and another six-axle diesel (again using an existing diesel).
These sets would allow heavy freight trains to run on both electrified and non-electrified lines.
What happens is that, on non-electrified lines, the electric locomotive acts as a slug, with its two trucks being powered by the adjacent diesels. On electrified lines, the diesels are shut down, and act as slugs, receiving their power from the electric locomotive.
Yes, the diesels would need some modifications, including controls to switch between modes, and some heavy-duty cables to carry power. But the whole set would be a lot cheaper than buying three new electric locomotives -- and having to change motive power at the ends of electric territories, particularly in the beginning when only a small amount of territory was electrified.
The modifications on the diesels would also include block heaters to keep the prime movers from freezing when shut down -- and making them easier to start.
I would, of course, begin by electrifying major tunnels, thereby greatly increasing their capacity -- with not having to wait for diesel exhaust to be vented.
Yes, this is a simplified version. In the paper, I addressed a number of other issues, including the fact that the transformer on the electric locomotive would need to have a higher rating than if the electric were only expected to operate on its own.
But, I hope you see that the general idea would work.
-- Ernest
But, for a more direct example:
A number of years ago, I wrote an analytical article that offered a solution for a transition period if/when freight railroads ever decided to electrify. Though an acquaintance, who is a (now retired) professor of electrical engineering (with some interest in railroads), said the proposal made perfect sense, I could never get any magazine interested in publishing it.
Basically, this is the idea: You set up 3-piece motive power sets consisting of a six-axle diesel (using existing diesels), a new electric locomotive, and another six-axle diesel (again using an existing diesel).
These sets would allow heavy freight trains to run on both electrified and non-electrified lines.
What happens is that, on non-electrified lines, the electric locomotive acts as a slug, with its two trucks being powered by the adjacent diesels. On electrified lines, the diesels are shut down, and act as slugs, receiving their power from the electric locomotive.
Yes, the diesels would need some modifications, including controls to switch between modes, and some heavy-duty cables to carry power. But the whole set would be a lot cheaper than buying three new electric locomotives -- and having to change motive power at the ends of electric territories, particularly in the beginning when only a small amount of territory was electrified.
The modifications on the diesels would also include block heaters to keep the prime movers from freezing when shut down -- and making them easier to start.
I would, of course, begin by electrifying major tunnels, thereby greatly increasing their capacity -- with not having to wait for diesel exhaust to be vented.
Yes, this is a simplified version. In the paper, I addressed a number of other issues, including the fact that the transformer on the electric locomotive would need to have a higher rating than if the electric were only expected to operate on its own.
But, I hope you see that the general idea would work.
-- Ernest
