Minuteman Mobility Test Train

A Minuteman Mobility Test Train was a Cold War train for Strategic Air Command testing before deployment of planned trains for launching Minuteman missiles which were to allow periodic movement for security from targeting by the Soviet missile force. At the time, the trains had the heaviest railroad cars used on regular rail routes, and rail sidings were surveyed during the trains' 1960 Operation Big Star (surveyed sites were subsequently used in 1961 by different SAC trains for evaluating bomber accuracy.)
Operation Big Star.
Operation Big Star was a series of US military exercises using 4 trains (of 6 planned) from the Hill Air Force Base rail terminal over "21 railroads in the Northwest and Midwest" during summer 1960.
The US Air Force Ballistic Missile Division conducted the tests while SAC had operational control of the trains with a "SAC task force" in Utah and on the train, military personnel and "civilian engineering, maintenance and logistic representatives" (the last 3 of the 6 planned trains were to leave from Des Moines, Iowa).
By November 16, ""no operational date [had] been set for the missile trains" and on December 13, 1960, a "full-scale mockup of a Minuteman train [was] in a big hangar at the Boeing Airplane Co. plant" (in 1959, the "assembly and recycle plant" had been planned "on the western end of Hill Air Force Base [Ogden Air Material Area] in the section formerly known as Ogden Ordnance Depot" and next to the Thiokol plant. Minuteman trains were cancelled on 14 December 1960.
Minuteman train fleet.
For the operational Minuteman trains planned with "five of the 10 cars [for] living and working quarters for the missilemen, including a control section where two launch officers [would] sit at duplicate panels…separated by bullet-proof glass", the Hill Air Material Area personnel were to rebuild existing Army-owned rail "cars to handle crews and equipment" ("missile launch cars would be specially built at Utah General Depot.") On January 27, 1961, a train was in Chicago "testing switching facilities" with "launching cars weigh 127 tons, equipped with four extra wheels to bear the weight of the 30 ton Minuteman, and a set of 12 hydraulic jacks to secure the missile in firing position" (the 1st operational train was planned for June 1962.)
The planned deployment with "Minuteman trains cost[ing] more than silo sites" was for wide-ranging operations to require the enemy's use of "more than 10,000 missiles against railroad trackage to immobilize the minuteman train fleet" of 150 missiles using of the US's of tracks by 1963. American Machine and Foundry and American Car and Foundry were to develop the special railroad cars, and the plan in December 1960 included use of a "radio-launch…network of antennae buried a few feet underground adjacent to each control tower."
The plan for Minuteman trains "had been shelved temporarily" by May 19, 1961, and on December 14, 1961, the Pentagon ended the rail program due to cost.
The 1st Utah-made Minuteman was shipped to a silo field from Air Force-Boeing Plant No. 77 in July 1962 in a "transport-erector vehicle" on a "special-built 85-foot flatbed railroad car", and a Peacekeeper Rail Garrison plan was announced by the Reagan Administration in 1986.