Engine 313 and Truck 31 returning from our funeral detail assisted Montgomery County units on a RV fire on Route 495 and River Road. Units were stuck in traffic coming across the American Legion Bridge, the crew of Engine 313 switched to a Montgomery County radio channel and was listening to units on the scene of a RV fire, as command requested additional units for water supply issues, Engine 313 advised command of their location and that we had 750 gallons of water if needed. Once on the scene Engine 313 provided water to Engine 706.