Electrical World, May 30, 1914, page 1269:
Radiotelephony for Railroads
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On account of the success that attended the wireless-telegraph installations on the Delaware, Lackawanna & Western Railroad during the nine-day paralysis of its wires in last February's blizzard the officials of that system have been investigating the possibilities of the radiotelegraph and radiotelephone on their moving trains.
Wireless-telephone apparatus was recently installed at Scranton, Pa., and on one of the through fast trains. The Scranton installation, though hurriedly made, was able on its second trial to maintain clear voice transmission to this train as far as to Stroudsburg, Pa., a distance of 53 miles, the train running at 60 miles per hour. The antenna at Scranton is 300 ft. long and 150 ft. high; that on the train extends over the four forward cars only, the station being in the second car from the locomotive. On account of train noises it is necessary to use an amplifier and a detector. A two-step amplifier giving from fifty to sixty times amplification, is used on the train. The generator is directly connected to a steam turbine in the baggage coach, which is supplied with steam from the steam-heating pipes beneath the car. At the Scranton station 125-volt direct current is used.
The present apparatus is of only 1-kw rating, but no difficulty has been had in telephoning from Scranton to Binghamton, a distance of 67 miles, over rough wooded and mountainous country. The officials of the Delaware, Lackawanna & Western Railroad purpose to make permanent installations on two of their fast-train equipments for facilitating dispatcher's service and especially for the convenience of the public.
In the radiotelephone equipment described a De Forest transmitter, an Audion amplifier and an Audion detector were used. These devices were built by the Radio Telephone & Telegraph Company, 309 Broadway, New York, which also made the installation at Scranton and on the Delaware, Lackawanna & Western train described above.