The last open house in the original home of MIT's Tech Model Railroad Club (TMRC) will be held on Saturday, April 6, in Rm 20E-214 from 10am-10pm.
The club is scheduled to move into comparable space in Building N52 as plans progress for the demolition of Building 20. Most of the current layout will be destroyed, although some parts will be saved for inclusion the new design.
The 600-square-foot model depicts the fictional Tech Nickel Plate railroad, which connects two cities and runs through forested mountains as well as industrial areas. Much of the custom-built cityscape was modeled after classic buildings in downtown Boston.
The layout includes two main tunnels, a trestle, rocky cliffs, rivers, dams, a mill pond, vintage cars, factories, and an operating streetcar line with live overhead wire. Its dense and complicated track plan is typical of those built in the 1950s, a "spaghetti bowl" no longer fashionable.
The model has more than 200 track switches and at least 1,000 feet of track, a good portion of which is hidden, so that it's often a challenge to figure out where the trains will reappear. All of the track was laid by hand: uncountable hours were spent placing ties individually on a roadbed, with nickel-silver rails hand-spiked to the ties. Track switches were built in place, with small pieces of rail cut to fit and soldered together.
Club members also designed sophisticated control systems to make the large layout very simple to operate and to reproduce driving a real train. The current control system was designed and built by MIT students in the mid-1960s. Engineers can run five trains at once on the main line while other engineers switch trains in the three large yards. The train operators watch a red/yellow/green signal, and the system prevents wrecks.
The members who worked on the control systems were key among the original computer hackers at MIT when machines like the TXO and PDP-1 were first installed.
TMRC was founded in 1946 and moved into Building 20 around 1948. Since then, more than 750 members-students, faculty and staff-have contributed to its developement. The open houses in Building 20 have attracted thousands of people, many of them parents hoisting fascinated youngsters onto their shoulders for a better view of the trains chugging through a wonderfully detailed world in miniature. For more information on the upcoming event, call x3-3269 or visit TMRC on the Web at
A version of this article appeared in MIT Tech Talk on March 20, 1996.