when did trains get two way radios?

I know that Pennsy used a system to transmit from caboose to engine and vice versa by low frequency magnetic induction to the pole line wires (reason for the external piping on engine and cabooses) that ran adjacent to train.  Not sure if dispatchers were tapped into wires so they could hear talk.  Unsure if this system would qualify as radio in the strict sense we know how radios are used today.

I think it was shortly after they bought one-way radios and then realized "oh! this isn't going to work"

The two railroads that I worked on in the 1970's (shortlines) did not have radios then.

John

The Erie definitely had radios by the early 60s, probably the late 50s.

Lee

The PRR "Train Phone" was installed on some of their steam power in the 1940s.

I also remember radios on the DL&W in the late 1950s, yet the B&O did NOT have radios during the fall and winter of 1962.   

I guess the 'first' was the PRR, as already stated. They experimented in 1946 with the induction method. I saw a picture of a yardman with 'portable' radio. The guy had on what looked like 3 large Hoola-Hoops around his mid-section, for the antenna, and a backpack for the batteries and radio. the whole contraption  looked like it weighed 30 pounds!

In terms of having dispatchers in radio contact with trains for purposes of controlling movements or issuing orders, I don't believe that really became prevalent until the 1970/1980's.  When towers were still common across the country, dispatchers communicated with the tower operators who copied down whatever the instructions were and then passed them up to the train.

Curt

I don't think the PRR's US&S TrainPhone can be considered as radio. It was an induction system of electro-magnetic waves. The transmitter had to near a tower or the lineside 'antenna' to be heard. This is quite different to the RF (radio frequency) signal used in radio transmitters.

True, all EMF produces a magnetic field, but there is a big difference in magnetic output of a radio transmitter (small) compared to the induction trainphone.

BTW, the PRR could not use their trainphone under electrified catenary because the EMF surrounding the high voltage live wires interferred with the induction.

Santa Fe started adding radios to some locomotives and way cars in the late 1940's.  The project was continued until, by the late 1950's, all road and most yard engines had radios.

Hand-held radios were another story.  They had some big portable radios with a telephone receiver and a shoulder strap in the 1950's, but only had a few "pack-sets" -- hand-held portable radios -- in 1970, when I hired out.  Hand and lantern signals continued to be the standard until a UTU contract in the later 1970's required the railroad to furnish a packet for every Trainman and Yardman.