(first posted 10/1/2016) Note: While my name appears in the byline, it should read “Brophy/Niedermeyer” as Paul made significant contributions and improvements.
The 40′ high-floor coach with large underfloor storage became the standard configuration for practically all modern highway buses. But just who pioneered that? The 1956 Kassbohrer-Eagle was the first production bus of that kind. But there was a precursor to it, the 1954 GM PDX-4901 (“Golden Chariot”), a giant of a bus that GM had high hopes for, but one that was rejected by potential customers and never made it into production. Considering that GM utterly dominated the bus market at the time, and its other buses were copied by everyone else, the failure of the PDX-4901 is a surprising aberration.
The PDX-4901, intended to be called “Super Highway Traveler” in production, is an obvious melding of two of GM’s most legendary intercity coaches; the very successful 35 ft PD 4104 (top) and the 40 ft PD 4501 Greyhound Scenicruiser. The PDX-4901 was developed in 1954 with a goal of offering operators other than Greyhound a high-profile 40 ft model equivalent to the Greyhound-exclusive Scenicruiser. Its chassis and drive train were lifted straight from the Scenicruiser, but rather than having a split, bi-level design, it had a single high-level floor.
And when they said high-level, they meant it. The reason for all those steps is because unlike later high-floor buses, the driver sat up at the same level as the the passengers. In all subsequent high floor buses, the driver sits somewhat lower, meaning there are two or three steps up to the initial front level, and perhaps one or two more to get to the main seating area level. Since GM didn’t custom design the 4901 as a high floor bus, but just jacked the whole smaller bus up, this was the result.
Advantages? As you can see, the 4901 had three large luggage bays compared to the two and one-half of the Scenicruiser – more space for bags and packages…a little less distinctive, but more space efficient. And visually imposing, especially for 1954.
GM obviously had high hopes for the Golden Chariot.
And the reason behind the Golden Chariot moniker? GM initially hued the anodized aluminum siding in gold.
Which almost certainly explains the 1956 “Golden Eagle”, the first Kassbohrer-Eagle bus built for Continental Trailways in 1956. The Golden Eagle offered a premium level of service than the subsequent Silver Eagle, and presumably GM had the same thing in mind with its Golden Chariot.
Unfortunately, GM was as hamstrung powering the PD-4901 as it was with the Scenicruiser. Its Detroit Diesel division did not yet have a V8 version of the -71 two-stroke engine family, and the 6-71 was just not powerful enough. So they used the same dual 4-71 engines, each driving through a fluid coupling and then a three-speed manual transmission with a two speed splitter as did the Scenicruiser. As has been pointed out in several other articles, this power-pack, a compromise at best, had continual teething problems which resulted in significant maintenance downtime – other companies heard of these issues, and as a result, were wary of taking a chance on this coach.
So, as with the Mack MV-620-D, this was a one-off model. GM kept it, then later sold it – and up until the late 1960s, it was in operations (re-engined with the DD 8V-71 as were all of Greyhound’s Scenicruisers) with Aro Coaches, Inc., based in Chatham NJ. As to its current whereabouts, no one knows. It’s a shame that it hasn’t been saved, restored, and offered for exhibition like the MV-620-D. This is actually a more significant coach – while not successful, it was the first, high-level, single floor intercity model – the template in use by every intercity coach today.
GM would stay with the bi-level design with its “Buffalo” series of coaches from 1966-80, but did make one more attempt at a single high floor model in 1977 with the “Triton II” prototype.Unfortunately it was met with the same lack of enthusiasm as the 4901.
And as we’ve mentioned the GM Buffalo, we’ll look at these coaches in an upcoming post.