I rode the Sikorsky UAC more or less a dozen times between June 1969 and August 1971. I got to ride it almost new, since Penn Central put it in revenue service only 2 months before I first rode it (contrary to what some sources have published as having been 1968). Back then I lived in the Greater Boston area and would ride it to visit relatives in Queens, so since it terminated at GTC through June or July 1971, I had to take the IRT (NYCMTA) 42nd Street Shuttle and transfer to the 7th Ave local to 34th St. at NYPenn ─ then take the LIRR to Queens. For an 18,19-yr-old that was a cakewalk.
One seemingly insignificant but intriguing feature that most probably paid no attention to was the boarding doors. They were motorized doors that fit flush with the contour of the sides when secured closed. When being opened, they would plug inward and slide into a pocket to totally clear the opening ─ similar to the vestibule door operation of the then-new Budd Metroliners, except for the fact that the Metroliner doors didn't have the aircraft-like plug-flush feature. With the UAC doors in the open position at station stops with low platforms, such as at Back Bay and Providence, motorized steps would be deployed ─ the step assembly would be partially lowered (hinged outward) with two flanking tubular support arms, then unfold with rather elegantly engineered mechanical linkage, and finally land against the platform surface ─ all with a single button.
What I didn't particularly care for was the ride along the jointed-rail Shoreline of the former New Haven (Penn Central) at slow speeds, as the single-axle configuration and the pendulum struts between cars would annoyingly jerk the car ends back and forth when striking those staggered and depressed rail joints ─ worse than the norm with trucks on standard equipment and spring-load equalization. The lateral jolting would tend to harmonically dampen out at speed however. One thing that I recall most that at times would put me "on edge" was riding in the head-end mini-dome of the Sikorsky. The rapid approach at high speed to typically low-clearance bridges of New England induced a "head chopper" illusion that made me feel as if I should duck. I didn't get that feeling as much when riding the rear UAC dome, and when riding convention domes like Vista-domes, Pleasure-domes, Strata-domes, etc. at much lower speeds. I recall on my first round trip ─ a June Sunday return GCT to Back Bay, passengers in the forward mini-dome were watching ahead, when we narrowly avoided hitting a teenage girl crossing the tracks at Niantic Bay Beach. Just as with many other pedestrians, she likely hadn't stopped first and looked as we approached on a right-hand sweeping curve (northbound). I think the horn startled her, then becoming confused on split-second decision to dash forward or retreat, and either way she had almost no reaction time.
Other than being plagued with obviously crippling engine fires, the most frequent sources of trouble were the trainsets' gearboxes and cardan shafts (propeller shafts), which were prone to early failure. Lubrication had been a major issue with both USDOT-PC turbos and particularly with low-oil triggers in the Pratt &Whitney turbine engines and gear boxes, but fortunately before summer 1971, only one of the trainsets at a time was deployed for scheduled daily service. I always preferred the first revenue-service exterior livery in red, silver, and blue with black stripes, whereas Amtrak's schemes just weren't my "cup of tea". The acceleration was reduced a bit, once Amtrak added two intermediate cars to each set.
[photo - © Donald Haskel]