Optical Beam-Break Tunnel Route Selection

The route exiting the long tunnel can be selected while the train is in motion by extending an arm and breaking the selector light beam. The selector is mounted on the Cox Bridge at milepost 3.54, about 4 mileposts before the tunnel.

▸ Breaking the left beam will select the leftward diverging route leading to Central Station.
▸ Breaking the right beam will select the rightward diverging route to Back Shop and Main Yard.
▸ Breaking both beams will select the straight route to bond.
▸ Breaking neither beam leaves the previously used route aligned.

The signal system implements route stacking, so that breaking the beam will not throw the turnouts underneath any trains that are ahead of you. Once preceding trains clear the interlocking, the turnouts will throw to align for your chosen route.

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Tunnel Route Selection

A route selector box with push buttons is mounted on the wall inside These buttons override the primary method of route selection, which is the in-motion beam breaks. (See Tunnel Beam-Break Route Selector). The three-headed mast signal adjacent to the turnouts indicates the lined route. If the signal is indicating the desired route, then you do not need to stop to press a route button.


▸ The top head governs the straight route to Bond.
▸ The middle head governs the left diverging route to Central Station.
▸ The bottom head governs the right diverging route to the Main Yard.

The signal logic will never throw the turnouts when the signal is displaying anything but a solid red. Conversely, when the signal is displaying solid red, the turnouts may throw at any time if triggered by the beam-break route request. Therefore, do not "tailgate" another train and pass a red signal. Wait for your own indication on the signal before proceeding.

The blue lamps on the pushbutton box will display your route request, but confirmation that the route is lined is indicated on the mast signal. The yellow lamp on the box indicates that the turnouts are under manual control of the tower and the buttons will not work. Also be sure that the front of your train is behind the signal when pressing buttons. The turnouts will not throw if a train is in the interlocking.

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Central Station Route Selection

▸ The red lamps on the box indicate occupied tracks within the station.
▸ The yellow lamp indicates that the turnouts are under manual control of the tower and the buttons will not work.
▸ The blue lamps on the box will display the route request, but confirmation that the route is lined is indicated on the signal mounted on the signal bridge.

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K&W Junction Route Selection

Route selector boxes with push buttons are mounted next to the tracks approaching K&W Junction. These buttons will request a complete route through Grand Junction. The system implements route stacking, so that pushing a button at K&W Junction will not throw a turnout underneath any trains ahead of you. It is unnecessary to re-request your route at Grand Junction. The mast signals will indicate when your requested route is lined. You may have to wait for other train movements before your requested route is lined - be patient.

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Grand Junction Route Selection

Route selector boxes with push buttons are mounted next to the tracks approaching Grand Junction. If you have already requested a route at K&W Jct, it is unnecessary to re-request the same route at Grand Junction. The mast signals will indicate when your requested route is lined. You may have to wait for other train movements before your requested route is lined - be patient.

If you find you have selected the wrong route, you must back up until your train is behind the signals. You cannot simply walk back to the buttons. The switches will not throw while a train is occupying the interlocking.

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Dogwalk Bidirectional Track

The signals entering the bidirectional track normally display red and are triggered by the track circuits when a train approaches. Do not pass a signal that remains red, as it indicates that there is a train coming toward you on the single track.

The eastbound signal at the South Portal Circle also senses the position of the single-slip switch at that location. If the switch is positioned to continue around the circle to Rio Grande, the signal will remain dark. If the switch is positioned for the bidirectional track to Red Ant Jct, the signal will illuminate and govern this route.

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Fuel Depot to K&W Junction Reverse Movement

A second dwarf signal will protect your reverse movement through K&W Junction. Continue reversing completely through K&W Junction until the front of your train is completely behind the signal. The turnouts will not throw if a train is occupying the interlocking. Use the usual forward movement route request push buttons to request a route to the K&W as you normally would.

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Grand Junction to Fuel Depot Reverse Movement

When returning from the K&W to Grand Junction, it is possible to request a reverse movement backwards to the Fuel Depot. A fifth button mounted low on the pushbutton box is provided for this purpose.

Proceed forward through Grand Junction on signal indication as you normally would. Continue forward until the rear of your train is completely past the dwarf signals protecting a reverse movement. Once fully past the dwarf signal, it will then display an indication allowing reverse movement to the Fuel Depot.

While it may seem that travelling fully beyond the dwarf signal is unnecessarily far, it is actually prototypical. By rule, prototype trains are not allowed to reverse direction in an interlocking unless immediately protected by a signal. This has to do with how the route locking logic is implemented.

While reversing, you will be protected against oncoming trains from K&W Junction. Any trains leaving Crisp Yard will be routed around you on the other parallel track. The dwarf signal at the Fuel Depot switch will also be activated.

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Prototype Signals

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