Tech Model Railroad Club

The Tech Model Railroad Club (TMRC) is a student organization at the Massachusetts Institute of Technology (MIT). Historically it has been a wellspring of hacker culture and the oldest such hacking group in North America. Formed in 1946, its HO scale layout specializes in automated operation of model trains.

History

The first meeting of the Tech Model Railroad Club was organized by John Fitzallen Moore and Walter Marvin in November of 1946. Moore and Marvin had membership cards #0 and #1 and served as the first president and vice-president respectively. They then switched roles the following year.

Circa 1948, the club obtained official MIT campus space in Room 20E-214, on the third floor of Building 20, a "temporary" World War II-era structure, sometimes called "the Plywood Palace", which had been home to the MIT Radiation Lab during World War II.

The club's members, who shared a passion to find out how things worked and then to master them, were among the first hackers. Some of the key early members of the club were Jack Dennis and Peter Samson, who compiled the 1959 Dictionary of the TMRC Language and who are credited with originating the concept "Information wants to be free". The atmosphere was casual; members disliked authority. Members received a key to the room after logging 40 hours of work on the layout.

The club was composed of several groups, including those who were interested in building and painting replicas of certain trains with historical and emotional values, those that wanted to do scenery and buildings, those that wanted to run trains on schedules, and those composing the "Signals and Power Subcommittee" who created the circuits that made the trains run. This last group would be among the ones who popularized the term "hacker" among many other slang terms, and who eventually moved on to computers and programming. They were initially drawn to the IBM 704, the multimillion-dollar mainframe that was operated in Building 26, but access to and time on the mainframe was restricted to more important people. The group really became intensively involved with computers when Jack Dennis, a former member who had by then joined the MIT Electrical Engineering faculty, introduced them to the TX-0, a $3,000,000 computer on long-term loan from Lincoln Laboratory.

At the club itself, a semi-automatic control system based on telephone relays was installed by the mid-1950s. It was called the ARRC (Automatic Railroad Running Computer). It could run a train over the entire set of track, in both directions, without manual intervention, throwing switches and powering tracks ahead of the train. A mainframe program was used to compute the path, and all modifications to the layout had to be compatible with this ability. It was sometimes used to clean the tracks with a track scraper car. Sometime around 1964, this was replaced by a second system built around the Number 5 Crossbar telephone switch; the lead designer for this project was Alan Kotok, by then a rising star on the design staff at Digital Equipment Corporation (DEC). Equipment for this effort was donated by the telephone company via the Western Electric College Gift Plan. An extension to the basic control system allowed TMRC engineers to control switches on the layout. There was also a digital clock display with relay switching, and an internal telephone system with external tie-lines, all built from telephone stepping switches and relays.

The system of telephones was used for voice communication, for control of the clock, as well as for control of switches and blocks. Additionally, " ''j'' trains" (imaginary trains) could be run by use of plugs in the control system.

Around 1970, Digital Equipment Corporation donated two small rackmount PDP-11 minicomputers. One was eventually used to operate the club's major freight yard and the other was set up to perform user interface tasks, such as initial assignment of trains to throttles, and to throw turnouts. The computer replaced the keypad unit from an old keypunch machine which had been originally installed by Richard Greenblatt.

Vocabulary and neologisms

The TMRC spawned a unique vocabulary. Compiled in the TMRC Dictionary, it included terms that later became part of the hacker's Jargon File, such as "foo", " mung", and "frob