Long cars present a variety of challenges for model railroads. From 72 foot passenger cars to 89 foot flatcars, long equipment could be found in a variety of operating eras and they are more common today than ever.
From the minimum radius of your curves to the design of switch ladders there are lots of things to consider when designing your layout and laying track if you intend to have long cars. But what about changes to the cars themselves?
Many of the operating problems encountered with long cars come from adaptations made to the coupler assemblies to allow greater turning through tight curves. Manufacturers have gotten much better with these systems in recent years in all scales, but they can still cause problems.
Swinging couplers are most problematic when the cars are being pushed. When pulled, the couplers are kept in-line by the tension. When pushed, the extra flexibility allows the couplers to be pushed at odd angles. This in turn puts lateral stresses on the cars which help to push them off the rails. Even on straight track this can cause problems, but add in some curves or a switch ladder in a yard and you have a real potential for disaster.
In addition to complicating back-up moves and switching, these swing pockets often allow the couplers to remain off-center, making uncoupling on a magnet or even coupling more difficult.