http://www.thenewstribune.com/2012/11/08/2360477/sound-transit-train-gets-stuck.html#hyperlocal-headlines-default#storylink=cpy
One has to wonder if they had an AC traction loco there would have been no problem ?
The Morris and Essex Railroad* began commuter service in New Jersey during the second half of the 1830's. The engines had difficulty in the hills of west Essex County and when they did male passengers were required to get out and push.
The more it changes the more it is the same.
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*Later the Morris and Essex line of the Delaware Lackawanna and Western and now of New Jersey Transit.
This should get fun when the line is extended and Amtrak starts using the line for a shortcut.
An AC unit wouldn't have made a difference with the problem encountered - wheel slip due to a sander failure.
My understanding is that AC provides better adhesion without sanding as well as better adhesion with sanding. The reason is that when a slips starts with an AC unit, the torque to the wheel drops much faster than with a DC unit, thus allowing the wheel to regain traction must faster.
- Erik
erikem My understanding is that AC provides better adhesion without sanding as well as better adhesion with sanding. The reason is that when a slips starts with an AC unit, the torque to the wheel drops much faster than with a DC unit, thus allowing the wheel to regain traction must faster. - Erik
While AC locomotives have better wheel slip control than DC locomotives - they can't overcome all conditions without sand.
Never too old to have a happy childhood!
There is a hill in Tacoma near that area that is in excess of 3%. I watched the American orient express stall there with three units pulling it up the hill. I asked the engineer what throttle position he was in and he said he never even made it out of notch 3. He had wheel slip problems. The Milwaukee road used to haul log trains up that same hill and sometimes had in excess of 200 cars. They used to put 8 F-units in a mother slug combo in the middle of the train just to go up it. They also had some spectacular runaways coming down that hill.
No matter what technology a locomotive has it will always be limited by wheel slip. That is why many of the high horsepower locomotives (such as the AC 6000 rated at 6000 hp) were down rated in horsepower. All that horsepower means nothing if the locomotive is too light to keep the wheels from spinning. With your average 210 ton locomotive 4,000-4400 HP seems to be the best range for pulling heavy trains with out having wheel slip problems up grades. If you run out of sand regardless if it is a steam locomotive or diesel you are up the creek with out a paddle.
Or maybe if the engineer were able to tigger the sander manually instead of having to rely on a computer, the problem would have been avoided.
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