A railroad cross tie having an inner core with at least one longitudinally extending metallic reinforcing member and an outer casing. The cross tie includes first and second end caps. The first end cap is disposed proximate a first end of the inner core and the second end cap is disposed proximate a second opposite end. One embodiment of the cross tie includes an expansion gap longitudinally disposed between the first and second end caps. Longitudinal dimensions of the expansion gap varies in response to differential thermal expansion between the inner core and the outer casing. In other embodiments, the end caps are mechanically interlocked with the inner core and the outer casing overlays a portion of the end caps. The disclosed structures securely and reliably attach the end caps to the cross tie. A method of manufacturing cross ties is also disclosed.