You could use the ATLS system. It's like a radio controller that connects triggers, signals, traffic stoppers and crossing signals together to create almost any type of crossing you can think of. It's tricky to understand it at first, but once you get it, you will be very happy with it.
To start place an Object called ATLS CONTROLLER, it's a built in object. Then use the question mark to open it's properties to see the instructions. Press plus for the radio frequency and choose what frequency this crossing will have for all it's objects, then for Routes, press minus until you get to -1, that is LEVEL CROSSING MODE.
Read the instructions, and follow the links, just remember you only pay attention to the level crossing mode which some of the instruction / tutorials may not apply.
I would then download some BNSF50 crossing signals as they work very well with the system. Also search this forum for ATLS Help or Tutorial, etc.. there is a lot of help available.... Good Luck