TELECOM Digest OnLine - Sorted: Pioneer Cellular Mobile Telephone System: Metroliner Train Phones

Pioneer Cellular Mobile Telephone System: Metroliner Train Phones
27 Jul 2006 10:44:34 -0700

The following has an article from the Bell Laboratories Record about
the original telephone service provided on the Penn Central Metroliner
trains in 1969. This was the first application of the "cell" concept
of re-using radio frequencies and shifting frequencies as the vehicle
is in motion. While we take cell phones for granted these days, in
1969 the Metroliner service was a major technical advancement. There
were passenger radio-trainphones before Metroliner, but they were

The article notes:

- The system was two-way. Land based people could call any train by
giving the train number, location was not necessary. The equipment
automatically located the desired train along the route. An attendant
answered the call and paged the desired passenger.

- Calls could be paid by collect, credit card, or coin.

- Passengers would dial direct on a Touch Tone. Direct dialing and
Touch Tone on coin phones was a new concept in 1969.

- Service was provided in the five Baltimore tunnels and under Phila
30th Street by special antenna work designed for the underground
environment. I don't think service was provided in the Hudson River

- As mentioned, the system was cellular. The article describes some
technical details on radio transmission within the cells and separation
of the cells.

- Because calling traffic was expected to be heavy as the train
approached its end terminals, additional channel capacity was provided
in those areas.

- The train transmitters produce 12 watts of RF power.

- Every phone on a car is independent of other phones on a train.

- The system accounts for variation of train battery supply from 56 to
88 volts.

- The car antenna was protected from sharp brushes used in the carwash
and noise from the 11KV AC pantograph arcs and power cable.

- Base station transmission power design took into account terrain,
antenna heights, and distances between base stations so as to maximize
the signal up to cell boundaries but not far beyond.

The Metroliner was a marked advance in railroad passenger service. It
was very successful in attracting passengers back to the rails. But
the trains themselves had many technical problems. Amtrak eventually
pulled the original train sets and used other equipment instead,
keeping the name.

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