Is it typical for KCS (or any other roads) to mix 4 and 6 axle power on different types of trains? I know most all coal unit trains I see are running exclusively 6 axle (which makes sense). If memory serves me, most grain unit trains typically run 6 axle power. I was just pondering this the other day, and thought it might make an interesting discussion point. Thanks for the input!
That may be like mixing dynamic and non-dynamic brakes. I thiought it would be a big factor for MUing, but I saw many mixed lashups. It might not be optimum, but it may not make that much difference either. For the 4/6 axle issue, that may not make a difference either as long as the train has enough drawbar pull. Seems like some roads bought GP60s for stack trains because they were faster over the road.
Santa Fe (back in the 1960s-1980s), would mix 4-axle and 6-axle all the time. The 2nd and 4th engines are 6-axle, the rest look like 4-axle:
Beautiful picture John! Carl, mixing different motive power is still common, although with the new engines by GE and EMD starting to push the older stuff out, same unit MUed consists are getting more common. As far as 4 vs 6 axles, it makes no difference. The power planners look at the HP/Tractive Effort/Braking when assigning power to trains. Sometimes, extra engines might accumlate at a terminal, due to more traffic flowing in one direction, and then add the extra units to a train to be moved.
Still happens all the time on CSX and NS here in Georgia. Both are a little power short so like what OC mentioned, the planner give up just enough HP/Tractive Effort/Braking to get the train to it's next destination.
thanks for the info. guys. was considering getting more more locos to use as pushers for my grain drags and wanted to get something right, but still get the most bang for my locomotive buck.
In the book Contemporary Diesel Spotter's Guide from Kalmbach Publishing, Lou Marre goes into extensive (and I mean extensive) detail on motive power- what best to use where, matching diesels with different HP ratings, four & six-axle diesels in the same consist, and so on. It's aimed at mechanical engineers (or so it seems), but it's a well-thought-out treatise. It also covers mother-slug units. FTR, I've seen Frisco uso four and six-axle power on their main lines. One consist that stood out was the SD45/F9B/SD45 lashups on the Cherokee Subdivision, until all the Fs were gone in 1974 or so. Closest I have to that on film is an SD40-2/GP38-2/SD45 power set on an eastbound CTB, setting out a bad-order car in Afton, OK in the summer of 1980.
