@Mark Boyce posted:John, You would want to turn both the locomotive and tender coupled together. It would could be a real pain to unhook some tenders from their locomotives, and I have never heard of it done before on the prototype or models. I think the same would hold for any AB units for similar reasons. I don't have an AB set out to see how long they are. Less tracks off the turntable would be good to eliminate the curved ones. The 4-way switch for the yard saves space, but then you would need a runaround track on each side of the yard. I have 4% grades on my layout, and they are working alright on my short trains. I'm sure you would like to run longer trains than I can. I setup a temporary track and tried it at different grades with each of my engines pulling cars to see what would work. Remember that it takes a little more pulling power on grades than straightaways.
Hi Mark,
Loco & tender for post war Berkshire 736 is about 21" so no worries there for now. Illinois Central Diesel AB unit is about 28" And I can imagine the NYC K-Line would be slightly longer, about 33" for A/B units. And I now see that the 4-way switch is an issue with runaround tracks. Glad to hear your 4% grades are ok I was shooting for 3.5% max grade and will do the experiment you did with actual trains pulling a consist up that grade and around curves. Great Advise Mark, Thanks!