| Lionel 151 Semaphore | BACK |
A semaphore signal has a movable flag and can show a green or red light. It is employed to inform a train engineer of the traffic condition in the next track block. If the flag is vertical and the light is green the block ahead is clear; if the flag is horizontal, and the light is red, a train occupies the next block.
The Lionel 151 Semaphore was introduced in 1947 and is still available.
It is 9" high, making it a 1:48 scale model of a 36' high signal. While a bit tall for O Gauge, it serves well for a toy train layout: the semaphore flag is easy see.
The base, flag mechanism, and lamp housing are black diecast metal. The post, finial cap, and red ladder are formed sheet metal. The flag is painted plastic. A bayonet light bulb ( L53 , L363 ) is used. (Click the numbers for bulb specifications.)
Electrical connections for the 151 Semaphore are made to three terminal
posts on the base. The center post is common to the light and the arm; it
is usually connected to one side of a 12 volt accessory transformer. The
other two posts connect to the light bulb and the arm solenoid as shown in
the diagram. The light bulb and arm terminals are wired to the device for
controlling the signal.
The 151 Semaphore first came with a 153C contactor, then the 145C weight activated contactor.
The 151 Semaphore can also be operated with an insulated outside
track rail.
The 151 Semaphore can also be operated with with Three-Rail Innovations' Two-Relay Controller . The 2RC has many configurations for independently operating one or two 151 Semaphores. Multiple semaphores, say positioned facing each train direction for a track block, can be connected to each relay
Following examples will demonstrate many of the possible configurations and connections for operating semaphores. Any of the following 2RC features can be used:
The input is connected to an isolated rail section long enough to be called a track block. A semaphore is positioned at the beginning of the block so the engineer can see the signal before entering the block. If trains are running in both directions on the track, then a semaphore is positioned at both ends of the track block. Both can be operated with the same relay by paralleling corresponding 151 wiring terminals. Different trackside accessories at each end of the track block can also be activated with the same relay outputs. For example, semaphores used in a series of blocks in one direction, and block signals for the other direction.
The following diagram shows the general wiring for connecting a 151 to the 2RC. The light is always on. Select appropriate input and output connections for the configuration and operating feature used.
The following diagram shows the light and arm connected to the same 2RC relay. The light is normally off, on only when the semaphore is activated and the flag is horizontal.
The following diagram shows the light and arm connected to different 2RC relays. The relays can be on the same or different 2RCs. This arrangement allows for the most variety of operations.
With the inputs for the configured 2RC relays connected to the same isolated track section, different features can be used for the light and arm: say, "ON/OFF" for the arm and "Slow Flash" for the light.
With the inputs connected to separate isolated track sections, the light and arm can operate when the train is in different blocks. For example, if the block connected to the light is positioned before the semaphore, the light will be activated only when the train engineer can see it. Different activation features, such as "ON/OFF," "Limited," and "Slow Flash," can also be used.
Three-Rail Innovations' "Two Relay Controller" can be used to operate the Lionel 151 Semaphore in a variety of ways as trains move from track block to track block, allowing you to fully exploit the visitor appeal of this classic trackside accessory.