On the Keystone Secondary here, there were running 3 SD80MACs on teh front, nothing on teh rear. Now, it’s 2 on teh front, 2 on the back. Other locos are being used as well, and I don’t know to what extent train size has grown, but that got me thinking, what is the extent of the abilities of distrubted power in such situations? Anybody got some figures to help? Thanks.
If you’re expecting a savings in fuel or horsepower from the use of distributed power on any given train, you may be in for a disappointment. The use of DPUs has permitted longer trains to be run safely. They do two things: they provide better control of slack within the train, permitting the trains to exceed lengths that could be safely operated without DP, and they permit braking to be applied from two points in the train, allowing a service application of brakes to apply at least twice as fast, and minimizing the effects of slack action in an emergency application. These things translate into safety. The efficiency comes from being able to operate larger trains with the same degree of safety, which (especially in the case of unit trains) could eventually result in the reduction of trains needed to do the same amount of work.
Actually there is a fuel savings, Carl, as much as 10%. Which is huge. I heard from one of the Class 1s a couple days ago they now have 60% of their main-line train-starts as DPUs, which took me aback as I hadn’t realized it had grown that fast in the last year.
The railroads are extremely bullish on how the productivity gains of the last few years are going to make them money-printing machines when the economy starts growing again.
The next challenge will be to implement PTC without it decreasing productivity. It’s not going to be easy. There are some ways that PTC can really kill productivity and no one credible has figured out what to do about all of them yet.
RWM
The use of DPUs also reduces the strain on head-end couplers and helps prevent broken knuckles. Sometimes it’s a safety issue too, to prevent stringlining in mountainous terrain with a lot of curves.
The dp trains are fuel efficent as for example of some of my trians 115 coal hoppers loaded 2 engines on the head end I will burn 200 gallons of diesel per hour if I am 1 on the head and 1 on the rear I will burn about 180 gallons of diesel per hour, train handleing is much better 1 point is the trains air brakes it will pump air from each end as long as the remote unit sences a 1 pound increase at the control valve and slack is mannaged to the point where it is almost not their.
Rodney
When using distributed power, wouldn’t the slack in the train bunch up and cuse the lead locomotives to waste fuel ( the loco’s wouldn’t be pulling anything just themelves.)
I’m only quessing, but it seems to me that the last third of the train would have bunched up slack and the front third would have no slack and the middle would be kind of have a loose floating slack depending on the terrain. All the power will get applied somewhere. None would be wasted.