Hammond Tower was the crossing of the E/W Michigan Central and Indiana Harbor Belt railways, with the N/S CI&L, Erie and Nickle Plate railroads in Hammond, Indiana. According to [RAUS] this was a MC tower.
This is likely the first interlocking system installed by the Michigan Central. (The first in Michigan was likely at Wasepi, MI).
1884. May 24. Testing a Safe Crossing Signal. The system of Westinghouse electrical and pneumatic interlocking switches and semaphores which the Union Switch & Signal Company was put in for the Michigan Central, Chicago & Atlantic and Nickel Plate railroads at Hammond. Ind., was officially tested yesterday in the presence of Auditor-General Rice, of Indiana, Commissioner of Railroads lines, of Michigan, and a party of about twenty-five railroad officials. A special train of one coach and Supt. Brown's private car left Chicago for Hammond at 10 o'clock, with the officers of the three roads interested, and officials of the Louisville, New Albany & Chicago, which road will soon cross the Michigan Central at the same point, and is expected to also adopt the system if it is approved by Auditor Rice.
The test was satisfactory in every respect, the apparatus working to perfection. The system at Hammond is quite similar to the one in operation at Welling ton, O., which was examined by the last Michigan Legislature before it passed the law allowing railroads to dispense with stopping trains at crossings where such a system is in use, provided it is first approved by the Commissioner of Railroads. A similar law has been passed in Indiana also. But as that State has no Commissioner of Railroads, the approving power is given to the Auditor.
The test yesterday was made especially for the benefit of Auditor Rice. That officer expressed entire satisfaction with its working, but reserved his official opinion, which will be communicated to the roads interested in a day or two. In case he approves of it the roads will be saved great delay, as trains which have the right of way can run the crossing without first stopping, as all trains are now required to do. The Westinghouse system consists of safety switches (derails) and semaphore signals, all operated by one man. On each side of the crossing on each road is a short safety switch 400 feet from the crossing, terminating in a sand bank, a home signal 500 feet from the crossing and a distance signal 2,000 feet from the crossing.
One mile from the crossing is an electric enunciator, which warns the operator of the approach of a train. Unless a train is ready to run to the crossing, all the safety switches stand open and the signals are set at danger. When a train approaches on either track the operator first closes the safety switches on that track. This act closes an electric circuit, which enables him to drop the danger signals and give the train on that track the right of way. At the same time it locks all the other levers, making it impossible to open the switches or clear the signals on any other tracks.
The instant a train enters the section within the home signal it locks the entire set of levers, making it impossible for the operator to move one of them till the train has cleared the crossing. Then he must first raise his danger signal before he can open the safety switches, which were closed, or open another set. Perfect safely is thus insured, as the operator can make no blunders, no matter how confused or how hurried he may be. The track must be set right before he can permit a train to pass the crossing, and having given one road the right of way, he cannot suddenly change bis mind and give it to another. At the same time the engineer must obey the signals, and even if he disregards them he can do no serious harm, as he cannot reach the crossing.
If he makes the attempt be will find himself at the end of a short siding, plowing in a heap of sand, where his engine will stop in its own length. The power which opens and closes the switches and raises and lowers the signals is pneumatic, instead of hydraulic as in the Wellington system. At each moving point is one air chamber provided with a V valve very similar to an ordinary steam chest. This valve is thrown from one position to another by pressure from a small tube filled by a nonfreezing mixture of alcohol and water. The pressure required to move the valve is very slight, being applied by the operator by means of a small lever, which requires so little space that a dozen could be operated by one man, without moving his position.
Electricity does the rest, providing the locking power and insuring perfect safety. The moving of one lever the least bit, locks all the others. At the same time the danger signals cannot be cleared until the switch lever is moved to its full extent, and the switch is moved to its place and locked there. A piece of wood or any obstruction which prevents the switch from coming entirely over, prevents the lever which moves it from coming to its place, and renders it impossible to give a train the right of way until the obstruction is removed and it can cross with safety. By a very simple little device the distance danger signal can be raised when the home signal, is down, thus detaining a second train until the first on the same track has cleared the crossing.
Commissioner Innes expressed entire satisfaction with this system, and will favor its adoption in all the more important crossings in this State. He thinks that it leaves nothing to be desired and that the only thing which stands in the way of its general adoption is its cost. At the same time the Commissioner is determined to find some system of uniform crossing signals which shall be moderate in cost. He is now having prepared plans for a set of crossing gates similar; in operation to the interlocking switch system. [DFP-1874-0624]
1925. This interlocking was rebuilt, adding six levers. [RSC-1926]
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