PD-4501 Scenicruiser

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PD-4501 Scenicruiser
Scenicruiser Greyhound.jpg
Greyhound ad showing a Scenicruiser
Manufacturer GMC
  • Two 4.7L (281 ci) GM 4-71 I4 diesel (1954-1960)
  • 9.3L (568 ci) GM 8V-71 diesel V8 (after 1961)
  • Two 3-speed manual + 2-speed auxiliary gearbox (1954-1960)
  • 4-speed manual (after 1961)
Length 40 feet (12.19 m)

The GM PD-4501 Scenicruiser, manufactured exclusively for The Greyhound Corporation, was a three-axle monocoque two-level coach used by Greyhound from July 1954 into the 1970s. 1,001 were made between 1954 and 1956.

The Scenicruiser became an icon of the American way of life due to its presence throughout the USA in cities and along highways and popularity with the traveling public.

The high-level design concept of Scenicruiser resembles some of the rolling stock of the passenger-carrying railroads of the United States and Canada, particularly their popular dome cars. This type of two-level motorcoach body was common in the late forties in Western Europe, including Great Britain where it was known as Observation coach.[1]

The concept of two-level monocoque body had been used earlier in the Spanish Pegaso Z-403 two-axle coach, designed in 1949 and in production since 1951.[2]


The PD-4501, the most distinctive American parlor bus design of the modern era, was the result of five years of GM Truck and Coach Division effort based on a design by Raymond Loewy as U.S. Patent 2,563,917. The design is listed under the U.S. Patent D175,464 with Roland E. Gegoux as its designer. Originally conceived as a 35-foot (10.67 m) bus, Greyhound used a tandem-axle, 40-foot (12.19 m) prototype called the GX-2 to lobby for the lifting of restrictions against operation of 40-foot (12.19 m) buses.

Power was originally provided by two GM Diesel 4-71 engines driving through a fluid coupling because the 8V-71 engine was not ready for production. This installation proved to be less than successful, and the 979 buses remaining in 1961-62 were rebuilt with 8V-71 engines and 4-speed manual Spicer transmissions by the Marmon-Herrington Corporation.

The original design prototype for the Scenicruiser was a double decker with access from the first level. The driver would look to the road from the second level. It was soon decided that it would be a split-level instead, with a lower level containing the driving console and 10 seats behind it, and the upper level containing 33 seats. This arrangement also allowed a baggage compartment underneath the second level, while providing 360-degree view for the upper level. A lavatory was located on the rear of the first level. The Scenicruiser was equipped with air-ride suspension and air-conditioning.

The popularity of the Scenicruiser with the public and bus operators inspired GM's Buffalo bus models, which had a less obvious "second level" which ran most of the length of the coach, and smaller "vista windows" in the front (due to the driver and first passenger seats being positioned higher). These models were available for sale to all operators, unlike the Scenicruiser,and Greyhound bought only 362 of them. The Scenicruiser also inspired the look-alike Flxible VistaLiner and a coach from the Beck Corporation. Only twelve VistaLiners were built. All were delivered to Queen City Trailways. Most of the Beck coaches eventually wound up in Cuba for a time and later returned to the United States, but none is believed to have survived. A number of VistaLiners have been converted to motorhomes and are still on the road. GM "buffaloes" at Greyhound were of the model PD-4107, delivered to Greyhound in 1966-67. Greyhound bought 362 of those buses in two orders (162 in 1966 and 200 more in 1967) and eventually replaced them with coaches from Motor Coach Industries. [In 1958 The Greyhound Corporation had bought a controlling (majority) interest in the Motor Coach Industries (MCI), Limited, and in -61 it had acquired the entire ownership of it.]

Problems and effects on the North American bus industry[edit]

As introduced, the Scenicruiser had some significant problems, particularly the drivetrain and cracking around the side windows in the rear quarter of the coach. Initially

Maintenance on the Scenicruiser was a constant headache – partly because of the complicated nature of some of the new systems (in the manner of Rube Goldberg, some of the critics suggested), partly because some of the components were too new and unimproved (using new, unproved, and unimproved technology), partly because the diagnostic tools and techniques were inadequate, partly because the training and availability of mechanics (and maintenance supervisors and managers) for the new model were less than optimum, partly because the technical support and repair-parts support were less than optimum, and largely because of a combination of several of those factors – along with a few other explanations – including, sadly, occasional incidents of careless or intentional abuse of the new coaches by disgusted drivers or mechanics.[3]

Super Scenicruiser[edit]

In 1961 Marmon-Herrington rebuilt most Scenicruisers, a few having already been damaged in accidents. One major change was installing the newly-available Detroit Diesel 8V71 engine and a 4-speed transmission in place of the twin 4-71 engines and 3-speed transmission with 2-speed differential. Another change was adding side reinforcement plates above the rear wheels and below the windows. After the rebuilding a Super Scenicruiser badge replaced the Scenicruiser badge.

The cracking problems continued, however, and many Scenicruisers that made it into the 1970s had trim panels between upper side windows removed and further reinforcements added. Greyhound and GMC did not arrive at these repairs amicably, and in 1958, Greyhound purchased the remaining stock of Motor Coach Industries. Greyhound ordered thousands of buses from MCI and thus significantly reduced orders from GMC, although Greyhound continued to buy GMC buses in small numbers for nearly another decade as Greyhound's demand exceeded MCI's manufacturing capacity. GMCs intercity bus sales slumped, and in 1980 they exited the intercity bus market.


  • Length: 40 feet (12.19 m)
  • Width: 96 inches (2,438 mm)
  • Height: 131 inches (3,327 mm)
  • Wheelbase: 261 inches (6,629 mm)
  • Turn radius: 45 feet (13.72 m)
  • Powerplant:
    • 1954: 2x GM Diesel 4-71 engine
    • 1961 repowering: 1x Detroit Diesel 8V-71 engine
  • Transmission: manual, Spicer, 3-speed with 2-speed splitter originally (6 speeds altogether), 4-speed after repowering
  • Fuel Tank: 180 US gallons (150 imp gal; 680 L).
  • Seats: 10 on lower level, 33 on upper level. Total 43 seats
  • Luggage: 344 cu ft (9.7 m3).
  • Aisle width: 14 inches (356 mm)
  • Front door width: 26 inches (660 mm)

Survival and sequels[edit]

About 200 Scenicruisers survived when Greyhound replaced them with MCI buses. As of 2009, some of these remain, most privately owned, and many converted to motorhomes. Other owners are committed bus enthusiasts who have restored their buses to like-new condition, or put them to other interesting uses.

The success of the Scenicruiser pushed other North American coach makers to launch their own two-level models; among them the 1955 Flxible VistaLiner, the Western Flyer T-36-2L, the Beck DH-1000, and the impressive four-axle twin-steer Sultana Crucero Imperial.

The influence of the Scenicruiser may be seen in General Motors' 1964 Buick Sport Wagon and Oldsmobile Vista Cruiser station wagons, both of which had stepped-up roofs and a raised skylight over the second row of seats.[4][5]

Literary references[edit]

The Pulitzer Prize-winning novel A Confederacy of Dunces, by John Kennedy Toole, includes many obsessively sarcastic references by his main character to a trip in a Scenicruiser coach, which he recounts as a traumatic ordeal.


  1. ^ Whitson RC35C built on Maudslay, Leyland, AEC, and Foden chassis between 1949 and 1952 (accessed March 10, 2013)
  2. ^ Pegaso Monocasco (monocoque) brochure 1951 accessed March 10, 2013
  3. ^ Duncan Bryant Rushing. "Bluehounds and Redhounds, the histories of Greyhound and Trailways". Retrieved 7 May 2011. 
  4. ^ HowStuffWorks.com article mentioning possibility of 1960s GM station wagons being inspired by Scenicruiser Retrieved 2011-06-18
  5. ^ Eric Peters Autos page citing possible Scenicruiser heritage for the Vista Cruiser Retrieved 2011-06-18

See also[edit]

External links[edit]