the High Speed Ground Transportation Act of 1965, the other was CN Rail's desire to update their passenger service with the ending of "pooled service" (with CP Rail) between Toronto and Montreal. 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 design was similar to the original C&O version, but modified to use turbine power instead of diesel. The chosen engines were a modified version of the Pratt & Whitney Canada PT6 (also a UAC division) known as the ST6, downrated from . 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. The power cars had three engine bays on either side of the car and could mount engines in pairs for two to six turbines, depending on the needs of the carrier. Another ST6 drove an alternator to provide 'hotel' electrical power for the train. Each power car had a fuel capacity of . The turbine engines were smaller and lighter ( with accessories) than the diesels they replaced, so the original power cars ended up being much larger than needed. Instead of a major redesign, UAC re-arranged the interior of the existing layout. The control room "pod" on top was lengthened to produce a viewing area with seating, and additional seating was added along the main level as well. This produced the Power Dome Cars (PDC) that were long (tip of nose to trailing articulated axle, while the Intermediate Cars (IC) were long (axle to axle), considerably shorter than the -long conventional passenger cars of this period. 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". The single-axle bogies on