The expansion device of railway bridges is an important connecting component between the ends of railway bridges, which plays an important role in the expansion joints and waterproof performance of the bridge ends. Its quality and waterproof performance will directly affect the durability of the bridge deck structure. In order to ensure the durability of intercity rail transit bridges, reliable and durable waterproof expansion devices should be used between beam joints to protect the beam body and the lower structure of the bridge. This expansion device is suitable for large-span bridges in intercity rail transit with a speed of 200 kilometers per hour, where ballastless tracks are laid on the bridge.