(Updated 11/7/2026)
The 1954 GM PDX-4901, better known as the “Golden Chariot,” was an extraordinary bus that was decades ahead of its time. 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.
For years, its fate was unknown, and it seemed likely that this important piece of transportation history had disappeared for good. Now there’s good news: the long-lost prototype has been found, tucked away in a Massachusetts bus company’s storage facility, with hopes of a full restoration. It’s a welcome opportunity to revisit one of GM’s most intriguing experiments—and a bus whose influence far outlasted its brief career. 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 drivetrain 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 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 had 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 over 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 (see post-script below). 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.
Post-Script: Good news! When writing this post a decade ago, the most current information at the time was the Golden Chariot was “lost” and its fate was unknown. We recently learned that the bus had been found at Wilson Bus Lines in East Templeton Massachusetts, at the company’s long-term storage facilities. The backstory is interesting – Wilson Lines had operated the 4901 in the early 60’s, then later sold it. Wilson’s President found the bus in the early 80’s, bought it back, and planned on restoring it. Unfortunately, he passed away and the bus was buried in the back of the warehouse.
Some pics of its current state are above. Plans are for the bus to be completely restored. While the 4901 looks like it will need an extensive restoration, hopefully we’ll see it “out and about” soon. Thank goodness it’s been found and saved.
Note: While my name appears in the byline, it should read “Brophy/Niedermeyer” as Paul made significant contributions and improvements.
Related reading:
Bus Stop Classic: GM PD-4104 – The Most Dominant and Influential Bus Ever by PN
Bus Stop Classic: GM PD 4107/4108 and 4903/4905; GM’s Buffalo – Last Of The Line By JB
In new high floor buses, the head of the driver sits roughly at the same level as the passengers’ feet… In that featured coach, driving it must be like driving a COE truck, no??? Below the cockpit of a modern coach, just to illustrate the evolution of ergonomics in long haul coaches
It’s no wonder that people wax nostalgic for the 50s when even something as miserable as bus travel looks appealing because of the iconic bus designs of the day. Back then buses looked like buses. Modern buses look like road trolleys.
In my neck of the woods modern buses don’t look THAT bad… 🙂
With those headlights and side view mirrors, that looks vaguely like a large insect.
But when that face debuted in its predecessor (pictured below), back in 2001 it made a gynormous impact. Long haul coach market was never the same and the coachbuilder threw that face in pretty much everything they designed after ir. I’m sure CCer Johannes recognises both pictured (up and below. The upper one actually has DAF mechanicals)
Damn. You’d need a pickax and pitons to climb that cliff! The entry steps in the SceniCruiser were hard enough for older folks, but these would be physically impossible.
Not nearly as bad as it looks. The driver looks small in comparison to those steps because he’s further away from the camera lens, which is clearly distorting your perception. Their just normal height bus steps, in this case all at once instead of broken up in modern high floor buses. No difference, really.
I like those 1950s era style buses. New ones are boxy and boring. Bus makers should go to retro style buses, as auto makers have done with some cars. There was a 1960s era GM Greyhound I’d also like to see on CC, a smaller version of the so called “Buffalo Bus” and were quite common during my youth.
This is the one I was talking about , which I just found online, a 1964 GM 4106 , an updated 1954 4104. It’s not a smaller version of the “Buffalo” as I thought in my last post.
Hang in there Chris, there’s a post on the GM Buffalo coming up in a few weeks where we mention the 4106. Jim.
Thanks. I love those old Greyhound buses , because they bring back memories of summers with my grandmother , who didn’t drive , but liked to travel…
Why does it say “Scenicruiser Service” on the side of that bus that isn’t a Scenicruiser?
Just my guess but while the Scenecruiser was somewhat of a maintenance headache for Greyhound, it was a brilliant marketing move and a huge publicity success – and the company no doubt concluded it could increase ridership and profits by leveraging the Scencruiser “brand value.” Jim.
While “Scenicruiser” was originally only used by Greyhound to identify its exclusive GM PD-4501 coach, around the time the GM PD-4106 came out, and its entire fleet of PD-4501’s were refurbished and equipped with the new Detroit Diesel 8v-71 engine, Greyhound’s marketing department decided to use the well known and popular name to describe all air-conditioned, restroom equipped coaches in Greyhound’s fleet (older PD-4104’s and new PD-4106’s) as offering “Scenicruiser Service”.
The rebuilt PD-4501’s were renamed “Super Scenicruiser”…
Busses sounded like busses back in those days too…..when powered by Detroit 6V71 and 8V71 2 stroke diesels……EPA regulations in the US have forced cleaner 4 cycle design diesels into busses….they don’t have the classic roar of the old 2 strokes.
Had GM stayed with the Triton prototype, they could have even further modernized the exterior design as years had gone by and perhaps add two rear axles the other being a tag axle and smoother side panels. In addition, it wouldn’t be out of GM’s realm to perhaps even add a 45 Foot Version eventually which is currently now a common industry standard. This would ultimately give MCI (now owned by New Flyer Industries) and Prevost (owned by Volvo North American Bus Group) a run for their money.
I agree, the Triton could have made it to the 90’s, and use the B500 transmission and Series 60 engines.
People may say that this bus being modernized Buffalo, but the Classic was a modernized New Look, and it had a B400 with a Series 50 in it’s last years.
Roger Smith-era GM would probably not want to keep their Triton II coach line any longer than they kept the RTS and Classic transit bus lines, which would mean they’d most likely sell it to MCI alongside the transit buses in 1987. MCI would be almost guaranteed to axe the Triton II in order to prevent competition with their own models. Considering how good the competition was at the time (Prevost LeMirage, MCI MC-9, etc.) I don’t think the Triton II could’ve gone anywhere even if it was a clean-sheet product and not the more likely warmed-over Buffalo.
Massive and impressive machinery ! Keep them exotics (to my eyes) coming.
Especially when what we had in the 60s was this… Good looking, but totally different (pic from Pinterest)
That “Triton II” looks like someone chopped off the bottom half of a “Silversides” bus and the top half off a RTS and glued them together.
That Triton concept was an attempt to upgrade and modernize the GM PD4905 platform….That model, nicknamed the Buffalo bus was introduced in the mid to late 1960’s and was discontinued after 1980…..GM started backing away from the motorcoach business at that point after dominating the market.
My recollection from driving the PD 4501 as well as the “Buffalo” (in the 60s) is that the Buffalo came out with a 425ci Cat engine.
Ray
GM didn’t back out. They lost Greyhound as a customer…Greyhound had bought Motor Coach Industries,then a Canadian company ,ca. 1960, and originally had it build buses for Greyhound Canada. When GM and Greyhound had their falling out, MCI was ready with new models for Greyhound. These buses developed a reputation for reliability and quality, to the point that MCI got orders from non-Greyhound operators. With the loss of customers, GM decided to exit the over-the-road market in 1980.
The Buffalo bus was discontinued not because GM was backing away from the market but because, being begat from the New Look city/suburban bus, it lost its production facility when GM dropped the New Look for the RTS, which certainly was no boon to GM’s bus business.
That certainly played into it. But sales of the Buffalo had been dropping due to much stronger competition from MCI, Eagle and others. If GM felt the Buffalo still had a substantial future, it could have set up a separate line for it. It was pretty clear that GM was becoming less committed to the coach market.
You have a point…
And a correction to my post; where I wrote “New Look” I should have written,”Fishbowl.” Some sources, notably coachinfo.com, refer to the quad-headlight update of the “Old Look” as “New Look,” but “Fishbowl” is unambiguous.
Ironically, 1954 was the same year the Budd Hi-Level passenger coach was introduced on Santa Fe’s El Capitan (at 1st on a trial basis). With more revenue seats per car (72), & lots of space below as on the bus, it inspired Amtrak’s later Superliners (1st tranche by Pullman-Standard).
There are still Budd rebuild plaques on our old rebuilt Blue Line cars from 30 years ago. The CTA finally put in an order for new cars but they’re all on other lines. Other than being noisy though the old cars aren’t bad. The new cars all have a less seating more standing floorprint.
Thanks for this. I didn’t even know such a thing existed. One more case of a design well ahead of its time.
The “Golden Chariot” PD4901 is alive and well, it’s currently owned by Wilson Bus Lines in MA. It’s part of their Historical Fleet, along with one of the rare surviving Eagle Articulated.
I’m the proud owner of a 53 4104. Number 648.
Runs like a top. Love this ol girl sumthin ferce.
What a bruiser! Fascinating concept. Love the innovative design and engineering spirit of the 1950s. The Triton II is equally wild. Great article Jim and Paul.
Curious about the fluid coupling and 3 speed manual transmission – was that a semi-automatic, maybe no clutch? I assume no overdrive back then either. Not familiar with a 2 speed splitter, maybe that meant dual range?
Or was the fluid coupling related to the combining of the 2 engines?
Yes, the fluid coupling was just to join the two engines, ahead of the actual clutch. If one engine conked out, it would just stop driving the fluid coupling and thus automatically disengage.
Yes, the two speed splitter allowed splitting the gears on the three-speed transmission. And the clutch was operated via a solenoid.
There’s more details and pictures in my Scenicruiser post:
https://www.curbsideclassic.com/curbside-classic-gmc-pd-4501-greyhound-scenicruiser-everybodys-favorite-bus-except-for-greyhound-and-gm/2/
Interesting – I will check out the Scenicruiser post.
Thanks
I seem to remember hearing the 4901 was built with an eye towards Trailways, who had been trying a number of faux-Scenicruisers before settling on the Eagle. Perhaps Trailways would have been interested had it not been for the twin 4-71 powerplant. Flawed though it was, the twin 4-71 was probably the best option at the time for this coach and the Scenicruisers, the only other option would have been the 6-110, which was too large and heavy and had its own issues.
The MCI coaches, especially the MC-7 was a much tougher coach that the GM Buffalo and the Scenic Cruisers. The GM’s rode nicer and those Buffalo’s and Scenic Cruisers had huge baggage compartments. Back in the day Greyhound made tons of money shipping packages.
The Minneapolis Minnesota maintenance shop was huge, all in door storage for every bus.
The building interior was laid out around a long U shaped aisle, service side had bays perpendicular to the aisle on both sides. Aisle was wide enough to have bus’s parked in front of the service bays on both sides with plenty of room for running bus’s down the center.
The Ready room on the other side of the building had on side packed with coaches perpendicular to the aisle and the opposite side had two rows of coaches parked parallel to the aisle. Wish I had photos from back then to see how many coaches were packed in there. The ready room coaches were parked so tight if you had a coach that leaned left as it lost air and its pal on the left happened to lean right they might be leaning on each other.
To give you an idea of the length of the building you could do a 20 mph brake test in the ready room without going outside.
The ready room was also a little lower than the service side so when you got to the end of the service side there was a U turn, not tight at all, as you transitioned into the aisle into the ready the curve dropped down and really twisted the chassis of the coach. That’s were you could hear those GMC’s squeaking and groaning, especially the old 4501’s, that 8V-71 drive train was suspended on the rear of the coach and it seemed to swing out to the side by a couple of inches. At that time the 4501’s we had had millions of miles on them and were very flexible.
Hi.
I came to this thread searching for information regarding the GMC 4901. I have a packet of photos, promo booklets, and a 18 page detailed (everything from measurements to gear ratios to alarm sounds and lights to paint and lettering) 4901 specifications document from September of 1954. Some of the photos are other models. One of the brochures is the Golden Chariot and one is the 4901.
There is a correspondence letter between a GMC Sr. Transportation Planner and another GMC employee with attached picture about a 1970s RTX. The letter is from the 80s.
I am interested in selling the lot. I am happy to provide pictures and negotiate a price.
Thank you,
Bryan Gilmer
Lizella, Georgia
It’s good to know that this important piece of GM bus history has been saved and will be restored. Unfortunately that was not the case for the Kassbohrer articulated Super Golden Eagle that sat near Eugene for decades. It finally got scrapped.
The PD4901 looks like it has ’66 Ford Galaxy taillights mounted on the rear panel evidently grafted on post-production. sometime, maybe for temporary transport… Weird!
pic
Did the 4901 have a full driving tandem, or a drive axle and a tag or pusher (non-driven) axle configuration? The Scenicruiser had just a single driving axle and a tag axle, as I recall. It is incredible that the 4901 was found in a small town like Templeton! The whole back story would be very interesting, I suspect.
The 4901 used the same suspension as the 4501 Scenicruiser – one axle was powered and the other a tag axle.
This is a fine example of bodywork and interior layout technology outpacing powertrain technology since the Detroit diesel V-engines were not yet ready for the start of this series of coaches.
How ironic this was repeated today as I was just in the Pacific Bus Museum to see all their operational buses. Sat in a PD-4501 that is fabulous inside. Took another ex-Hornet volunteer with me who loves diesels and just bought a 1957 Chris Craft with a pair of Hercules engines. Have many a picture so should I write something up on the visit?
PD-4151
They noticed my Ambassador wagon outside and our Hornet hats and kind of asked about volunteering and maybe get certified to drive a bus.
https://youtu.be/4t9N1loAuDo?si=VesVLChV0-rVev3s
There were many reasons GM and Greyhound parted company, but it didn’t happen overnight after the PD-4501. Greyhound wanted exclusive coaches (like the Scenicruiser) and GM wanted to produce standard models that they were free to sell to any operator. The Scenicruiser was a major headache that did cause strife between GM and Greyhound, but in reality it was a case of GM building exactly what Greyhound wanted, problems and all. GM designed the 8V-71 retrofit for Greyhound even though the conversions were done by Marmon-Herrington and Greyhound themselves. Greyhound didn’t stop buying GM coaches after the Scenicruiser, in fact not only did Greyhound continue to purchase PD-4104’s, but also bought large numbers of the New Look Suburbans, PD-4106’s and PD-4107’s throughout 1960’s. With Greyhound’s purchase of MCI the writing was on the wall for GM, but it still took until the early 70’s (over 10 years after the Scenicruiser was introduced) before MCI could meet Greyhound’s needs. In addition, MCI for many years exclusively used GM Detroit Diesels in Greyhound coaches. And for the record, MCI’s vaunted Scenicruiser replacement, the MC-6, also had serious issues.
The Triton II was an interesting exercise, though it was likely doomed from the start. The biggest issue with it was that it was built like a New Look or Buffalo, and GM’s coach plant at Pontiac was being converted over to produce the RTS which was radically different. A possible solution would have been to build the Triton II at the Canadian Diesel Division where the New Look and smilar Chassic were still produced but that didn’t happen, possibly because of the renewed interest in the old reliable New Look was using all the plant’s production capacity. Which says something about the early RTS’s…..
Amazing that has been found. I am glad that someone is restoring it. Certainly a big project in everyway.