This Iconic $650,000 Bus Is So Heavy It Needed Two Engines Just To Climb Hills

One of the most recognizable buses in American history is the GMC PD-4501 Scenicruiser. Even if you don’t know the name of this bus, you’ve almost certainly seen a picture of one online or perhaps even seen one in person. If you’re old enough, there’s a high chance you’ve even taken one of these great buses between cities. Now, the very first production Scenicruiser built is for sale and the seller wants a staggering $650,000 for it. I’m probably crazy for saying this, but that might actually be a decent price for this piece of American bus and General Motors history.

The Scenicruiser currently for sale on Facebook of all places is PD-4501-001. This bus is the very first production example of the Scenicruiser built in 1954. These buses would serve Greyhound Lines for years before their retirement. Just 1,001 units were built in the mid-1950s, of which only about 220 are known to exist today.

You’d think, then, that the very first Scenicruiser would be in Greyhound’s fleet or maybe somewhere at General Motors. Of all of the Scenicruisers built, just this one has stayed in Greyhound’s hands for its entire existence. Most recently, it was a part of the Greyhound Historic Collection. Sadly, Greyhound began parting ways with the collection in 2022 after the bus line was acquired by Munich-based FlixBus and its former owner, British transport conglomerate FirstGroup, sold off its Greyhound assets to Twenty Lake Management LLC.

Tons of Greyhound assets, including whole depots, were put on the chopping block. Not often reported was the disbandment of the Greyhound Historic Collection. Some buses have been sent to museums while PD-4501-001 remains in limbo. In November 2022, its listing price was a mouth-watering $950,000. Now, it’s still for sale for $650,000. It’s a shame because this bus marks an important part in both Greyhound and GMC history.

A Real Piece Of History

The Scenicruiser was one of the wonderful creations of General Motors back when it dominated all things diesel. From my retrospective:

Yellow Coach Manufacturing Company was opened in 1923 in Chicago by John D. Hertz. If that name sounds familiar, in 1923, Hertz bought out the Rent-A-Car rental company and changed its name to Hertz Drive-Ur-Self, which is today known simply as Hertz. That was hardly Hertz’s only business. In 1915, Hertz started the Yellow Cab Company in Chicago and also in 1923, Hertz started the Yellow Coach Manufacturing Company as a subsidiary of Yellow Cab. The coach arm of the business was responsible for the manufacture of buses. General Motors purchased a majority stake in the business just two years after its opening.

At the time, most buses were built with a body-on-frame design. One of Yellow Coach’s innovations back then was a monocoque structure. It started in 1936 with the Model 719 highway bus, which featured a transversely-mounted diesel engine in the rear and an aluminum monocoque construction. In 1940, the bus that would become the Old Look would get the same technology. When the GMC Truck and Coach Division absorbed the rest of Yellow Coach in 1943, this basic design layout would continue to see use in the rest of GM’s bus legends. For example, my RTS bus was built out of five-foot sections of stainless steel unibody.

The engineering might of General Motors was unrivaled. Someone alive in the 1970s could have ridden between stops in a GMC New Look city bus, gotten between cities in a GMC PD-4501 Scenicruiser bus, and traveled across the country on a train pulled by an Electro-Motive Division SDP40F in Amtrak livery. GM built just about everything that moved but large commercial airliners.

This story takes us back to the roaring period immediately after World War II. Bus travel was still a preferred way to traverse much of the United States. While planes were getting more popular, buses were still seen as the method for most people to travel long distances. In 1947, Look magazine reported that bus travel was the fastest-growing form of transportation in America, so it was crucial for bus lines and bus builders to put buses on the road that people wanted to ride in.

As Curbside Classic notes, from 1940 until well after the war, the PD-3751 “Silversides” was the bus of choice for Greyhound. The PD-3751 took the monocoque construction pioneered by Yellow Coach and paired it with reliable Detroit Diesel power. At the time, only GM buses had Detroit Diesels, which meant they had a huge advantage in both coach design and power.

There was a time when Greyhound was such a huge name in the bus line market that it had the pull to demand designs from bus manufacturers, not unlike how airlines buddy up with aircraft manufacturers. In 1944, Greyhound announced that it had begun development of a 50-passenger bus that was the same length and width as its existing buses, but managed to fit 9 extra passengers by going to a double-decker layout. This new bus would have carried more passengers without violating regulations on the length of intercity buses.

A patent was filed and in 1945, the Consolidated Vultee Aircraft Corporation (Convair) and General Motors were both given contracts to build prototypes of the new bus. Unfortunately, both companies would drop out of their contracts just a year later, forcing Greyhound to do it alone. As Motor Trend notes, the styling of Greyhound’s new bus would be handled by the famed Raymond Loewy. His designs reflected the optimism of the era with large windows, sleek aerodynamics, and intricate details in metal. The gorgeous behemoth, which could have been perhaps the prettiest bus ever built, was dubbed the “Highway Traveler.”

The first Highway Traveler prototype, the GX-1, was built by Greyhound’s own engineers. This 35-foot bus had room for 37 people on the upper deck and 13 people down below. The configuration allowed Greyhound to stay within state length restrictions while adding passengers.

The GX-1 presented Greyhound with a number of challenges. A double-decker all-metal bus is heavy, which meant that Greyhound needed a substantial engine. Greyhound found that Detroit Diesel didn’t make an engine that was powerful enough. Hall-Scott made an engine with enough beef to move the massive bus, but it consumed fuel at epic rates, so Greyhound landed on a weird idea: The line would power its bus with two air-cooled V6 engines from the Aircooled Motors Co., the same engine supplier that gave the Tucker 48 its distinctive engine. As Curbside Classic notes, Greyhound figured that the bus would run on one engine most of the time, but fire up the second engine for high loads like hills.

The GX-1 was put into revenue service for testing, but the bus would eventually return home and end up forgotten. Greyhound’s next iteration came with more help from General Motors. The General sent a 35-foot PD-4151 over to Greyhound, where Loewy worked his magic and Greyhound’s engineers modified the GM bus to their specifications.

In 1948, what they ended up with was the GX-2. This time, the resulting bus was a 40-foot beast with two rear axles. The GX-2 wasn’t a true double-decker. Instead, Greyhound borrowed a concept used by multiple bus builders before it. The forward compartment held 10 seats and a restroom while the raised compartment had seating for 33. Raising the bus behind the front end meant the bus could carry lots of luggage and perhaps even packages, making each trip potentially more lucrative.

The GX-2 was a headache for Greyhound. Length restrictions were still in place, so Greyhound spent years lobbying states to allow for its longer bus. At the same time, this bus didn’t solve the problem of needing a lot of power. An empty GX-2 weighed 26,100 pounds and tipped the scales at 34,485 pounds when loaded. This time, power would come from a 7-liter Detroit Diesel 6-71 straight-six. This engine made all of 200 HP and GM tried to give the engine help in the form of a porting job, cams, and even derestricting the engine’s RPM, but it was clear one engine just wasn’t going to cut it.

The Scenicruiser

The bus, called the Scenicruiser, was punted to GM to finalize and its engineers came up with the PD-4501. The Scenicruiser borrowed a lot of its technology from the PD-4104, which came a year before. The new bus had a smooth air suspension, aluminum panels over a monocoque construction, large windows, a fresh design, and Detroit Diesel power. Its upper deck allowed most passengers a wide view of the open road ahead while the massive baggage compartment promised additional fortunes.

However, unlike the PD-4104, the PD-4501 got really weird in the engine bay. See, a PD-4501 weighs about 29,000 pounds empty, towers 11 feet high, and these buses were built in 1954 before the advent of the relatively compact and strong diesels that buses have today. How did GM get around that? The company took two of its 4.7-liter Detroit Diesel 4-71 straight-fours and plopped them into the engine bay.

These engines were mounted side by side longitudinally and connected via a fluid coupling that was controlled by a solenoid-operated clutch. The driver shifted a three-speed transmission with a two-speed auxiliary transmission, giving a total of six gears. Greyhound says these engines power the rearmost axle and together pump out 300 HP. Torque should have been somewhere in the ballpark of 800 lb-ft. Starting was interesting as just one of the engines had a starter. Once one engine started, the other would start through the fluid coupling.

Greyhound touted the double-engine setup as not only a great source of power, but also redundancy. The bus was engineered to run on just one of the engines, so if one failed it wasn’t the end of the world. A Scenicruiser would just carry the dead engine to the next shop, get a new engine, and get back on the road. Greyhound made sure to stock engines along Scenicruiser routes just for that purpose. A special dolly was created with the idea of allowing Greyhound shops to quickly swap engines and accessories quickly. Quick-disconnect couplings were deployed all over the engine bay to make these swaps faster.

While the Scenicruiser quickly became a transit icon, it was a headache for Greyhound and General Motors. The innovative drivetrain setup wasn’t reliable and so many buses ended up broken and sidelined that the Scenicruiser availability rate cratered. As Curbside Classic notes, Greyhound got so desperate for reliable Scenicruisers that it sent a bus to Mercedes-Benz in Europe in hopes that maybe the Germans had a solution.

It should also be noted that, according to Bus Conversion Magazine, losing an engine also wasn’t a particularly good experience. The right engine controlled the air-conditioner, so if you lost that you’d have to drive a 160 HP sweatbox. The left engine controlled power steering, so if you lost that engine you’d be sweating in an air-conditioned 160 HP box. Oh, and you had to seal the exhaust of the dead engine because if you didn’t, the roots blower of the living engine could pull debris into the dead engine, killing it even further.

Unreliability wasn’t the only problem, either, as the PD-4501s also sometimes suffered from structure cracks. This would be a problem to impact later GM buses, too, like RTS-II engine cradles.

Eventually, Greyhound had enough and had a public spat with General Motors. It ordered 1,000 Scenicruisers and got 1,001 examples after the last prototype, EXP-331, was converted to PD-4501 spec and given serial number 1001. Greyhound stopped there, which meant that Scenicruiser production ended in 1956. General Motors also faced an anti-trust lawsuit and that year, the manufacturer’s monopoly on Detroit Diesel engines ended. Now, competing buses could get DD power, too.

Greyhound would later throw its money all-in on Motor Coach Industries (MCI), never looking back. But while it still had GM coaches Greyhound would invest in upgrades. In 1959, Detroit Diesel launched the 8V-71, a 9.3-liter V8 diesel that made 318 HP right out of the box, or more power than the Scenicruisers had from two 4-71s. Greyhound passed $10 million to Marmon-Harrington to upgrade the Scenicruiser fleet. The twin-engine complicated drivetrain was thrown away. Each bus was repowered with a Detroit 8V-71 and a more conventional four-speed manual transmission, solving the power issues once and for all.

Despite their problems, the Scenicruisers were beloved by riders for their comfort, their unforgettable style, and the views out of those large windows. Greyhound’s competitors buddied up with other bus manufacturers to make buses with similar specs and looks as the Scenicruisers, but none of them would gain the fame as the Scenicruiser.

Greyhound began phasing out the Scenicruisers in the early 1970s and by 1978, just a few were still in the Greyhound fleet. The bus line didn’t like the idea of selling these buses second-hand to its competition, so it tried to sell the old Scenicruisers to bus lines outside of America. Greyhound got few bites, which meant that most of these buses eventually met the crusher.

The influence of the Scenicruiser was also a big one. Larger 40-foot buses became more popular and riders craved large windows with tons of visibility. While the Scenicruiser and its competition eventually became old news, those old enough to have ridden on these buses still have fond memories of them. Greyhound was proud enough of the Scenicruiser to keep the very first production example for all of these years. The bus has gone to meetups and shows, providing perhaps more smiles than many other historic coaches out there.

This bus, fleet number 1954, is an interesting one. It is the very first bus off of the production line, but it technically isn’t the first Scenicruiser. The EXP-331 prototype, which is owned by Tom McNally, was built earlier, but it wasn’t converted to production spec until 1956. So that bus is technically both the first and the last.

Anyway, this bus is serial 001, or the very first of regular production, and it’s a time capsule in every sense of the term. Greyhound has kept this bus in pristine condition and it has been through at least one restoration. I’m not sure you’ll find a more authentic Scenicruiser in existence. Power comes from a Detroit Diesel 8V-71 and is shifted through a four-speed manual, so you don’t have to deal with the wacky dual-engine setup, either.

Honestly, this bus should probably go to a museum, but it’s been for sale for nearly two years and sadly, its future is still in limbo. The bus is currently for sale on Facebook by Michaud Bus Services in Los Angeles, California. for the whopping price of $650,000. I want to say the price is almost worth it, maybe?

It’s the very first production Scenicruiser and probably the best one that you’ll find in existence. But then the entirety of its value will be in the fact that it’s a cream puff museum piece and a great part of transit history. Turning it into an RV wouldn’t be the right thing to do, so you’d be spending $650,000 just to display the bus somewhere. So, I’m not really sure. What I can say is that I’m in love and I wish I could take it for a drive.

(Hat tip: homestarrunner.net: it’s dot com on our Discord!)