The arms included air springs to smooth out the motion, although it still felt "odd" while the train navigated short turns in switchyards and stations.

This left enough room for a passageway to run between the engines and under the pod to the nose of the car, where a coupling and doors were hidden behind a pair of movable clamshell covers.

[citation needed] United Aircraft Corporation (UAC) purchased the C&O patents to enter into the DOT's Northeast Corridor Demonstration Project.

The TurboTrain was designed by personnel of the Corporate Systems Center Division (CSC) of UAC, at Farmington, Connecticut.

The chosen engines were a modified version of the Pratt & Whitney Canada PT6 (also a UAC division) known as the ST6, downrated from 600 to 300 hp (447 to 224 kW).

The PT6 uses a "free turbine" that acts as a torque coupler, so the new design did not require a transmission and was able to drive the powered wheels directly.

[5] The turbine engines were smaller and lighter (300 pounds or 136 kilograms with accessories) than the diesels they replaced, so the original power cars ended up being much larger than needed.

[citation needed] The ability to connect trains together remained largely unchanged, although the routing of the internal passage changed slightly to rise up into the observation area of the pod, then back down under the control room and from there to the nose.

The Turbotrains were evaluated by multiple journalists in the Canadian press as having "rail noise that substantially exceeds that of standard equipment" and having poor riding characteristics, especially on curves, with one journalist stating that "the single-axle articulation in practice negotiates curves in a series of short jerks rather than the smooth flowing motion promised in press releases".

[9] After its construction at the Pullman yards in Chicago, the Turbotrain was sent eastward on August 1, 1967, at regular speed and without passengers, to Providence, Rhode Island, in order for UAC Aircraft Systems engineers to tear it down, study it for further development, and then eventual high-speed testing on the PRR's specially-rebuilt track between Trenton and New Brunswick, New Jersey.

[10] [11] In a competition with a GE powered Metroliner on the Pennsylvania Railroad's main-line between Trenton and New Brunswick, New Jersey, on December 20, 1967, one of the TurboTrains reached 170.8 mph (274.9 km/h).

[citation needed] In September 1976, Amtrak ceased revenue runs of Turbotrain trainsets and moved them to the Field's Point Maintenance Yard in Providence, Rhode Island, pending any possible sales to CN.

[14] An additional attempt was made to sell the units to the Illinois Central, but the poor mechanical condition of the trainsets caused the deal to fall through.

Large beams just behind the nose, designed for this purpose, absorbed the impact of the collision and limited the damage to the fiberglass clamshell doors and underlying metal.

[7] Technical problems, including brake systems freezing in winter, required a suspension of service in early January 1969.

[7] At this point, the CN management publicly expressed great dissatisfaction with these trainsets, with one vice-president claiming, "the trains never did measure up to the original contract and they haven't yet"; the manufacturer United Aircraft Company publicly claimed that CN suspended Turbotrain service for relatively minor technical problems.

From transmission to suspension to auxiliaries, far too many vital components seemed to have been translated straight from the drawing board to the series production line.

[19] The sale of the surviving Power Dome Coach car was cancelled, and it stood spare until a sister unit caught fire and burned in September 1975.

[20] By 1974, after substantial modifications of the gearbox device and pendular suspension, and reinforcement of the sound insulation, the Turbotrains finally took up untroubled service.

[citation needed] The Turbo's final run was on October 31, 1982, when they were replaced by the all-Canadian LRC trainsets from Bombardier Transportation, which employed conventional diesel-electric locomotives.