For a little used line crossing a high capacity main, the RRs don't like Diamonds. The wheels beat on them and wear them out. It is hard on the wheels too. Plus it requires reduced speed. So a RR prefers not to have a diamond on its tracks.
A simpler solution than moving parts was installed at Durand Mi a few years ago. There is a diamond there where the GTW mainline crosses what is now a low-speed shortline. The new diamond they put does not break the GTW rails. They are solid and can maintain speed. The shortline rails rise up higher than the flange and go over top the GTW. So they have the gaps and their flanges may actaully ride the GTW rails, but they are low speed and infrequent anyway. So they ramp about 2 inches or so, whatever it takes to get the flange up over the other rails, cross both rails and then ramp back down.
