At East Alleghany, at the west end of the old single track Lewis Tunnel, there was previously a 24 lever, electromechanical plant, which included the end of double track switch and the switches for the east end of two sidings which extend westward to Alleghany. When the new Lewis Tunnel was completed and the double track extended from Jerry's Run to East Alleghany, the track layouts at these two points were revised accordingly.

At Alleghany, 1.25 miles west of East Alleghany, the track layout includes several crossovers and switches to handle the west end of the two passing tracks and connections to the two main tracks extending westward through the separate single track Alleghany Tunnels, the summit of the grade approaching from each direction being located about 600 ft. East of the east portals of these tunnels. For eastward tonnage trains, the helper engines are attached at Hinton, W. Va., 51 miles west of Alleghany, and are cut off at Alleghany. For westward trains, they are attached at Clifton Forge, 29 miles east, and are cut off at East Alleghany. The track layout at Alleghany and at East Alleghany is arranged to facilitate cutting the helpers off, and for moves to and from the turntable at Alleghany.

Prior to the installation of the CTC machine, a 32-lever mechanical interlocking machine was in service at "A" Cabin, Alleghany, to handle the switches and crossovers at the west end of the passing tracks and for controlling the home interlocking signal, including remote control of the signals at the west end of old Alleghany Tunnel, near Tuckahoe, W. Va. During the construction of the new tunnels, temporary changes were made in the track layout at three old interlocking plants which required a rearrangement of the interlocking facilities, and after the tunnel work was completed, arrangements were made to extend the westward passing siding at Alleghany so that it would hold long freight trains. The extension of this siding made it necessary to rearrange some of the crossovers and switches at Alleghany.

The track changes in connection with the extension of the westward siding involved major revisions in the interlocking arrangement at Alleghany which would have made it necessary to install a new interlocking machine, and as it was desirable to arrange for train operation on either direction by signal indication on both main tracks through the territory - Tuckahoe to Jerry's Run- it was decided, as part of the program, the logical procedure would be to abandon the three old interlocking, install power-operated switches and signals, and control all these facilities from a new CTC type machine in a new tower to be known as "A" Cabin, located just west of Alleghany station. By arranging the signals for either-direction operation on the two main tracks, train movements would be greatly expedited in case of land slides or trouble developing in one of the tunnels. Furthermore, it would permit turning one of the tunnels over to track or other forces for certain hours of the day, thus facilitating their work. Another advantage of either-direction operation is that run-around movements can be made, thus keeping all trains moving rather than putting one of them on a siding.

The switches in the general vicinity of the tower are operated by electro-pneumatic switch and lock movements, while low-voltage electric switch and lock movements are used at Tuckahoe, East Alleghany and Jerry's Run, with the exception of the switch at the east end of the eastward passing siding at Jerry's Run, which is a spring switch. The signals throughout the entire territory are the color-light type. All signals are located immediately to the right of the track governed, standard two-arm signals being provided for all through train movements. Color-light dwarfs displaying two, three and four aspects, as required, are used to control low-speed train movements.

The CTC type control machine in "A" Cabin is arranged in two panels, the end section at the right being set at an angle with the main section, so that the operator can readily reach any of the levers without leaving his chair. The machine has 15 levers for the control of 7 single switches, 2 derails and 6 crossovers; 23 levers for the control of 44 signals, 2 traffic levers and 4 levers for the control of electric switch locks and as selector levers on hand operated switches. The levers are of the usual miniature type, each lever being equipped with indication repeater lamps, so that the leverman knows the position of each switch and the aspect of each signal. An illuminated track diagram, mounted just above the levers, indicates the location of all trains on the main tracks in the five mile controlled territory.

Mounted in a small case to the right of the CTC machine is a one lever controller used for the control of the ventilating fans for removing locomotive smoke from the westward Lewis Tunnel. Normally, the operation of these motor driven ventilating fans is controlled automatically by track circuits as a train approaches the tunnel. However, provision was also made for the fans to be operated manually when desired. This is accomplished by the operator at "A" Cabin throwing the lever in the "down" position to cause the fans to operate independent of the track circuit control. On the other hand, when a passenger train is being run through the tunnel, for which it is not necessary for the fans to be operated, the operator can cut off the track circuit control and prevent the fans from operating by throwing the lever to the "up" position. A yellow lamp on the CTC machine is lighted when the fans are in operation, and a red lamp is lighted when the fans are not in operation. The control of the fans is by direct wire, but the indications between the fan house at the tunnel and "A" Cabin are transmitted by code.

"A" Cabin is a block office for the delivery of train orders when required. Two color-light type signals, one for eastward movements and the other for westward movements, are mounted on the track side of the tower, and are designated as train order signals. These signals are controlled by a small two-lever controller mounted on the operator's desk at the right of the CTC machine. The levers are normally on center and the signals normally dark, indicating no orders. When the lever is thrown down, the signal displays a yellow aspect indicating that a non-restricting "19" order is to be delivered, but when the lever is thrown up, the signal displays red indicating that the train is to stop for a "31" or restricting "19" order. The aspect displayed by either signal is repeated on the controller so that the operator knows that the signal aspects correspond to the position of the lever, and he also has a check against a burned out lamp bulb. Under normal operating condition, train movements in the territory from Jerry's Run to Tuckahoe are directed by signal indications without written train orders. The orders, when issued at "A" Cabin, are ordinarily with reference to moves or track conditions beyond the control zone.