|Here's a good model of the original Lionel Block Signal from Mikes Train House at a very affordable price compared to original. Brilliant, highly visible signal lights turn from green to red when a train passes, and back to green when the next block is clear. Fascinating to watch the signal lights change as a train progresses down the track. All metal construction, AC or DC Operation, Bright-baked enamel finish, measures approximately 8" tall, Traditional tinplate styling, Easy to use thumb screw wire posts, Includes 18 volt bayonet bulbs. Set contains 1 signal and track activation device.