The expression "traverse" is not the railways' property, but it can as described also be used for railway rolling stock and locomotives etc., although to highlight the difference between the rail-vehicle traverse, which is fitted with rails 1435 mm apart for standard gauge and sometimes with extra rails to accommodate other gauges, and traverses which are merely flat aprons on wheels (like the railway traverse) to move other devices, I would use the word "machinery", or maybe "equipment". The expression "rolling stage" would never be used in a railway context.