The Tech Model Railroad Club (TMRC), a student organization at MIT, is one of the most famous model railroad clubs in the world. Formed in 1946, its HO scale layout specializes in automated operation of model trains.

Additionally, the TMRC is one of the wellsprings of hacker culture. The 1959 "Dictionary of the TMRC Language" compiled by Peter Samson included several terms that became basics of the hackish vocabulary (see especially "foo", "mung", and "frob").

It was at the TMRC that the word "hacking" was coined (followed later by "hack" and "hacker"). It was also at the TMRC that Steve Russel invented the first computer game, Spacewar.

By 1962, TMRC's legendary layout was already a marvel of complexity (and was to grow further over the next thirty years). The control system alone featured about 1200 relays. There were scram switches located at numerous places around the room that could be thwacked if something undesirable was about to occur, such as a train going full-bore at an obstruction. Another feature of the system was a digital clock on the dispatch board, which was itself something of a wonder in those bygone days before cheap LEDs and seven-segment displays. When someone hit a scram switch the clock stopped and the display was replaced with the word "FOO"; at TMRC the scram switches are therefore called "foo switches".

Design-wise, the layout is set in the 1950s, a transition period when railroads operated steam, diesel, and electric engines side by side. This allows visitors to run any engine they want without anything looking out of place.

Steven Levy, in his book Hackers (ISBN 0385191952), gives a stimulating account of those early years. TMRC's Power and Signals group included most of the early PDP-1 hackers and the people who later became the core of the MIT AI Lab staff. Thirty years later that connection is still very much alive, and a recent dictionary of hacker slang accordingly includes a number of entries from a recent revision of the TMRC dictionary (via the Hacker Jargon File).

In 1997 TMRC moved from building 20, a "temporary" World War II-era structure, to building N52, the MIT Museum building. As a result, the majority of the layout was destroyed. A new layout, under construction, is controlled by System 3, comprising around 40 PIC16F877 microcontrollers under the command of a Linux PC. An unusual feature of the layout is a 20-story building from the MIT campus, replicated in HO scale and wired with an array of window lights which can be used as a display for playing Tetris, in reference to a legendary (but apocryphal) MIT hack.

References

From the 1960s until very recently, train operation was controlled through a telephone cross-bar relay system. Control included of all switches, electrical "blocks" of track, and the clock. Certain codes would automatically set the clock, set the clock speed, and set the clock to "FOO" which usually indicated that something had gone wrong.

External links

• TMRC from MIT
• TMRC Dictionary