In all the cases I was involved with, the curving limit was driven by the coupler length and swing of the locomotive and those same factors of the vehicle it's coupled to; the limit of the single unit curving is always a lesser radius. For many years I've been fascinated with the 8 axle turbines and U50's with their truck attached couplers and draft gear, similar to many scale models for dealing with tight curves. To deal with the increasing locomotive length over that last several generations, I once proposed a 3 axle radial truck with integral draft gear/coupler/endplate, but got a very chilly reception from the rest of the organization.
Dave
A smaller engine would only be a matter of fuel economy or marginal weight reduction, and if either of those is a concern I think re-engining with something other than a GM locomotive two-stroke would be a wise idea.
Ironically, the G6B resulted from the Victorian Railways trying a smaller four stroke engine. This was the Mercedes Benz MB 820 b, a V-12 of 650HP, installed in a locally built locomotive of Krupp design with a rod coupled 0-6-0 wheel arrangement. Unfortunately the MB 820 b suffered from cavitation in the water jackets but the unfamiliarity of the whole concept made the "W class" unpopular from the start and production stopped half way through the order.
https://www.victorianrailways.net/motive%20power/wdie/wdie.html
As a result of this episode, any fuel consumption penalty with the 6-567C was accepted without question. In cidentally, alone amongst 567C engines in Australia, the 6-567C developed its 600HP at 800 rpm rather than the usual 835 rpm. The 6-645E was rated at 750HP at the usual 900 rpm.
Incidentally, Overmod mentioned balance problems with the 8-645E. I know there were problems with the 8-567C, which resulted in a revised firing order in the 8-567CR which appeared in the third and subsequent orders of G8B. There were quite a few 8-567CR and 8-645E engines in Australia, many still in main line service. These units are used on light lines in grain service, but tend to stay on the train with larger power on the steep grades over the mountains to the export ports.
Peter
I worked around industry railroads that used used rail and used ties on a gravel bed. One of these railroads borrowed a geep from a major railroad that derailed. The major railroad had to bring mobile crane to rerail the locomotive. It was decided to only use small locomotives.Gary
IA and eastern I worked around industry railroads that used used rail and used ties on a gravel bed. One of these railroads borrowed a geep from a major railroad that derailed. The major railroad had to bring mobile crane to rerail the locomotive. It was decided to only use small locomotives.Gary
Sounds like something that the mudchicken has mentioned repeatedly. The industry operation is going to have to spend some bucks on track maintenance and upkeep or they might wind up with derailments of standing cars.
Wonder of wonders these industry railroads ran for years with no derailments but some class 1 railroads had branches that were that bad with very little trouble because the speed limit was 10 mph. Gary
Most branches with 10 MPH speed limits generally had triweekly or less frequent service and were a few steps away from abandonment. A sizable industry operation with trackage more elaborate than one or two spurs will have to spend some money on maintenance.
I worked for companies cut every corner they could. Some midwestern railroads had branches that had triweekly service 9 months of the year with something like SW1 with maybe 5 cars but in the fall ALCO RSD5s and Baldwin roadswitchers would haul 30 to 50 cars a day on a 5 days a week.Gary
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