Mack Once Built A Bus That Looked Like A Giant Version Of Your Favorite Classic Chryslers

Some of the most famous Chrysler products in history have come from the marque’s iconic “Forward Look” era. Design chief Virgil Exner penned low-slung, long cars adorned with sweeping curves and prominent fins. Forward Look cars looked graceful, futuristic, and fast. Have you ever wondered what might happen if you scaled Forward Look design up to a commercial vehicle? The closest thing might be this, the Mack MV-620-D. This beauty, which even had tailfins, failed to unseat General Motors as the king of people movers, but it might be one of the best-looking classic buses to ever hit America’s roads.

Much of bus history is filled with the efforts of General Motors and its total domination of the market. Back in 1925, General Motors purchased a majority stake in the Yellow Coach Manufacturing Company, the bus arm of Yellow Cab. One of Yellow Coach’s greatest contributions to bus history was the 1936 Model 719 highway bus, which featured a transversely-mounted diesel engine in the rear and an aluminum monocoque construction. This bus was built during a time when most buses were still body-on-frame designs. Unitized construction was so influential that the buses of today are still built that way.

Yellow Coach was later absorbed into the GMC Truck and Coach Division. The buses built by GM’s bus division were so good that from the 1930s to the 1970s, General Motors had such a strong grip on the transit bus and intercity bus markets that everyone else was fighting for second place at best.

GM bus icons from history include the PD-4501 Scenicruiser, the New Look, and the RTS-II. Chances are, if you look at historical photographs of cityscapes, you’ll see a GM bus in the background, or a GM competitor’s bus that still looked like a GM bus.

Those fighting for the scraps left by GM include the famous Flxible, Twin Coach, Eagle, MCI, and some others. One brand that doesn’t get nearly as much attention as even GM or Flxible was Mack, the bulldog of the trucking world, but also once a producer of attractive buses.

Mack Made Buses Before Trucks

One of the most interesting vehicles for me at the 2025 New York International Auto Show was not some new car, but the 1925 Mack AB brought by Mack Trucks. The Mack of today is known for its heavy semi-tractors. In my area, Mack trucks are often seen pulling dump trailers between worksites. I also see the occasional Mack highway tractors delivering the goods around America. Yet, as Mack points out, the company’s first vehicle was a bus:

John Mack had already spent years researching and experimenting with his own design for a motorized wagon by the time he and his brothers opened their first bus manufacturing plant in 1900. The work paid off the same year, when the brothers introduced their first successful vehicle — a 40-horsepower, 20-passenger bus. The Mack bus, built for sightseeing concessionaire Isaac Harris, operated in Brooklyn’s Prospect Park for eight years before being converted into a truck. The success and acceptance of “Old No. 9” initiated a history of truck development unparalleled in the industry, and established a company whose reputation for tough, high-quality products has since become “part of the language.”

The brothers were also doing automotive repairs at this time.

Mack used a slogan in advertisements for many years, especially when we produced buses… ”The first Mack was a bus and the first bus was a Mack.“

The Mack Brothers Company entered the auto show circuit in 1904, displaying the Manhattan, its first bus put into series production, to the press at Madison Square Garden. Mack would later introduce innovations in the trucking history, and it all started after Jack took a ride in a 2-cylinder Winton car. The company was one of the pioneers in cabover trucks, smoothed out shifting with constant mesh transmissions, and even introduced a feature that let truckers skip gears when changing up or down. If you want to read more about Mack’s big truck ascension, click here to read more of my previous story.

Mack Rides The Rails

One fascinating bit of Mack history is that it spent much of the early 20th century building vehicles for public transit. Between 1905 and 1930, the company says, it built various railcars and locomotives. One vehicle Mack was known at the time for was its railbuses.

Now, the railbus might sound a whole lot like a streetcar, and they sort of have some parallels. A railbus started with a chassis featuring railcar bogies and often an automotive-type engine. On top of this chassis sat a custom bus-type body. Railbuses were light-duty transit vehicles and often rode down existing rails that would be shared with typical trains

Streetcars also looked like buses, and at their core, sort of functioned like buses. However, streetcars were usually purpose-built and, as their name implies, they drove down rails embedded in streets. The motor bus replaced the streetcar in countless cities around the world.

Above is a cool example of what Mack built, a Model AC railbus. These railbuses had a chassis and drivetrain by Mack, featuring a 64 HP four-cylinder gasoline engine and a hood ripped right off of a Mack truck. A coachbuilder handled the body.

The railbus was a huge deal in the 1920s. These were relatively compact vehicles that were far cheaper to run than steam trains, and were able to come to a stop and accelerate back to speed quickly – a feat much more difficult to achieve with steam power. Slapping train wheels on a bus was seen by many as a better alternative for branch lines than a dedicated train service. Mack was a popular railbus builder and went up against the likes of Fairbanks-Morse, White, and the Osgood Bradley Car Company.

After World War II, light passenger train technology advanced, with many designs moving away from their roots of being a bus with train wheels. From 1951 to 1954, Mack built ten FCD forward control diesel railcars. These looked a bit like a streetcar or an interurban, but these were still firmly railbuses, albeit really snazzy railbuses.

Mack’s historical pages also point out that the company wasn’t just building railbuses either. It also built self-propelled railcars.

Mack also started building locomotives around 1921. These locomotives used a pair of Mack 40 HP AC four-cylinder engines and worked in yards as switchers.

Later, Mack switcher locomotive configurations featured locomotives with up to four engines, electric traction motors, and even electric connectors to allow multiple Mack locomotives to be lashed up and operated together.

By the early 1930s, Mack’s gas-electric locomotives began to take a shape that railfans more associate with switcher units today (above). These blocky rigs were beastly, too, with advertisements claiming sizes as high as 80 tons and outputs as high as 540 horsepower. Advertisements pitched Mack’s gas-electric locomotives as powerful and cheap to run alternatives to steam locomotives.

The Mack Truck Of Buses

While all of this was happening, Mack also focused on advancing buses. By the 1920s, Mack buses reportedly gained pneumatic tires. As The Henry Ford writes, Mack’s earliest buses went to sightseeing firms. Mack would also get into school buses, and while it wasn’t the first to make a school bus with an all-steel body, Mack was an early adopter.

The 1930s saw Mack experimenting with a fascinating development, as the company began outfitting its gasoline buses with electric transmissions. This setup used the ICE to power a generator, which in turn operated an electric motor driving the rear axle. While interesting to see on an ICE bus, this wasn’t anything new, as electric trolley buses had already used electric motors for decades by that point. Having the electric transmission also eliminated the need for the driver to shift gears, because that electric motor makes torque from zero RPM and can continue to an RPM much higher than that of an internal combustion engine.

Around 1938, Mack began outfitting its buses with diesels, creating diesel-electric buses when the electric transmissions were added in. Mack wasn’t alone here, as Yellow Coach also had its own ICE-electric buses, too.

Mack’s buses became practical works of art after World War II. As Curbside Classic writes, Mack sold around 13,000 buses between 1900 and the war, and it wasn’t ready to quit yet. The brand hit the ground running after the war with the 1946 C-41. These buses measured 33 feet long, carried 41 passengers, and bore the aesthetics of the buses that enthusiasts refer to as the “Old Look” today.

Early editions of the C-41 had a 672 cubic inch straight-six gas engine bolted to a two-speed Spicer 184 “Turbomatic” torque converter transmission. These were known as Mack C-41-GTs, and like other buses of the era, the naming carried a meaning. “C” was the series, “41” was the passenger capacity, “G” indicated a gas engine, and “T” indicated a torque converter transmission.

While Mack wasn’t as popular as General Motors, it still found loyal customers. Detroit loved these buses enough to buy 332 of them and then ran them for nearly two decades. Later C Series variants would include larger buses, diesel buses, and even a facelifted model with bigger windows and a new face.

Something that made Mack’s buses different was that the company did not take the same unitized construction route as General Motors. Instead, Mack’s buses featured beefy integral welded subframes. This made the buses a few thousand pounds heavier than the GM competition, but the transit agencies that bought them liked Mack buses for their durability. Mack even boasted about bus durability with its “Fortress Frame” marketing.

As Curbside Classic notes, the ridiculously strong Mack buses had a sort of downside, and it was that, due to their heavy weight and large engines, they weren’t as cheap to operate as other buses. However, in fairness to Mack, General Motors dominated the bus market so hard that everyone else didn’t even come close.

In the 1950s, Mack wanted to expand its bus lines even further. Intercity coaches were a big deal and yet another market that General Motors dominated. But Mack found a potential way into the market.

Trying To Beat GM At Its Own Game

GM’s 1954 PD-4501 Scenicruiser would go down in history as one of the most iconic buses of all time. However, its career had a rocky start. The Scenicruiser weighed a whopping 29,000 pounds when empty, which was a bit of a problem since the diesel engines available for the bus market were underpowered for such a huge bus. GM’s solution was to drop in a pair of 4.7-liter Detroit Diesel 4-71 straight-fours into the Scenicruiser’s engine bay.

GM customer Greyhound touted the twin-engine Scenicruisers as having lots of power and redundancy for greater uptime. In reality, the twin-engine setup was so unreliable that the redundancy didn’t work out, and buses were often broken down and sidelined. It was a rare misstep for GM’s bus division, and apparently, Greyhound wasn’t all that pleased.

Making matters worse was an antitrust suit between the U.S. government and Greyhound and GM for the debacle with the Scenicruiser. According to National Bus Trader Magazine through the Morning Call, Greyhound responded to this suit by soliciting other bus makers for a new design.

In 1956, Mack bought C.D. Beck & Company, a bus manufacturer that had built intercity buses since its founding in 1931. Unfortunately, Beck would later gain a reputation for building buses that, at best, looked inspired by GM’s designs. But unlike GM, C.D. Beck didn’t have transit companies lining up to buy its buses. Reportedly, Mack was interested in Beck’s fire apparatus. However, Beck also had an additional carrot with its decades of experience in building intercity buses. By this point, Mack had left the intercity coach market for a long time, and buying Beck gave Mack some more buses to sell.

Mack would rebrand Beck’s Cruiser as the Mack 92-G, and a later model was called the 97-G. These buses were built at Beck’s facilities. According to Bus Transportation magazine, Greyhound purchased 34 Mack C-59 buses not long after Mack acquired Beck. This was only an appetizer, as Mack had big plans.

Mack’s biggest push to Greyhound was a pair of new bus concepts, the Mack Model 9700 and the MV-620-D. The latter bus originally had the name of Mack Visionliner 39, or MV-39.

The ‘Forward Look’ Of Buses

Reportedly, the 1957 Mack MV-620-D was designed by Beck engineer Donald Manning. If you’re a bus nut like I am, you probably know Manning more for his work on the GM RTS-II bus. Manning’s design for the MV-620-D demonstrator called for a 40-foot body and a triplet of axles. Motive power for this bus was the inclusion of a single Mack END 864 diesel V8. This beast had a large displacement of 864 cubic inches (14.1 liters) and made 255 HP and 638 lb-ft of torque.

This was less power than the 320 HP offered up by the twin-engine GM Scenicruiser, but crucially, the Mack had just one reliable engine rather than GM’s goofy setup – but let’s forget about that engine for a moment here. Check out the design of the MV-620-D! It featured bright colors, graceful curves, fluted brightwork, and even a pair of tailfins. This wasn’t touched by Chrysler’s Virgil Exner, but the MV-620-D looks like it could have been inspired by Chryslers of the same era. The bus included a bathroom, a five-speed manual transmission, and a two-speed axle for a total of ten gears.

Unfortunately, the coolest part of the bus, its Space Age design, was also its biggest problem. Other 40-foot buses had space for more than 40 passengers. However, since the passenger compartment of the Mack ended sooner, it had space for only 39 passengers. As the Morning Call reports, the reason why the MV-620-D has such a high beltline is that Greyhound requested a bus that could carry both packages and luggage in its bays.

Reportedly, Greyhound put the unit into service on its routes between Chicago and Los Angeles and San Francisco. Ultimately, Greyhound passed on both the Model 9700 and the sole MV-620-D ever built, returning the latter to Mack in 1960. Mack then sold the bus to a New York tour bus company, which later sold it to another company.

The bus ended up back in Mack’s hands in the early 1970s, where it was used as an executive shuttle. The MV-620-D was purchased by Charles Wotring of the Royal Coach Company in 1990 and then restored. The bus is currently in the hands of a private collector and has made appearances in museums, including the America On Wheels Transportation Museum.

It’s not known exactly why Greyhound passed on the MV-620-D, but one reason could be because of the 1959 launch of the Detroit Diesel 8V-71. Now, Detroit Diesel had a single diesel V8 that made more power than two inline fours. Greyhound upgraded its fleet of Scenicruisers with the new engines, probably choosing to do these overhauls to the fleet rather than replace those still relatively new buses.

Today, the MV-620-D is a sort of white whale for bus fans. Only one exists, and even the most dedicated bus fans might spend decades before ever seeing the coach in person. While the bus may not have been what Greyhound was looking for, it remains one of the most distinctive buses ever built in America. I mean, how many other buses have ’50s-style tailfins? If you own this bus or know its current owner, I’d love to know more. Contact me at mercedes@theautopian.com

Also, be sure to check out this video!

Top graphic image: Royal Coach via eBay Listing