The Clark CT-30 or “Clarktor” is hardly a marvel of engineering, and yet it continues to trudge on day-in and day-out, yanking luggage at airports around the world. Short, roofless, and with a thick steel plate on its face, the Clarktor is a unique and charming-looking machine, and it turns out it is way, way older than you think. It’s not only a World War II veteran, it actually hails from before the Great Depression.
While at the LAX airport on my way to Vancouver, I couldn’t help but take some photos of some luggage-tugs, and as I went to post them to Instagram, I realized that I knew very, very little about these little machines.
So I did some digging, and what I realized is that these things are truly ancient.
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The company that first made those baggage tugs (or towing tractors, or simply “tugs”) is Clark, and like many vehicular outfits in the U.S., it started in Michigan:
From day one, Clark was an industrial machinery company, building the “world’s first internal combustion-powered industrial truck” known as the Tructractor. As you can see in the image above, it was a rear-engine, rear-wheel drive, rear-seat, front-bed flatbed truck.
And believe it or not, only ten years later came the first Clarktor, and it looked much like the luggage tug we all know and love. Yes, in 1927 — almost 100 years ago!:
Clark Material Handling Company, which now makes mostly Forklifts, describes the first Clarktor, writing:
The Clarktor tow tractor is introduced. The Clarktor was used to pull airplanes and warehouse trailer trains. It was equipped with an electric self-starter, the first industrial truck or tractor to have this feature as standard equipment. The Clarktor remained in production until 1987.
As far as I can tell, Clarktor towing tractors really became prominent in the airline world sometime around World War II. The Delta Museum describes what was (and may still be) the company’s oldest bit of GSE (Ground Support Equipment, though the Delta Museum calls it “service equipment”):
This 1940s Clark “Clarktor” baggage tug was the oldest piece of ground service equipment owned by Delta Air Lines when it was restored in 1990.
The tug was purchased from the U.S. Department of Navy by Northeast Airlines in December 1961, for $5,000, and came to Delta when two airlines merged in 1972. It spent most of its life at New York-LaGuardia airport, and finally at Denver airport until late July 1989. At the time of its restoration, it had been overhauled five times and traveled over 53,000 miles.
The World War II-era Clarktor was the “Clarktor CT-6.” You can see one tugging munitions here on the bottom left during the Korean War efforts. Here’s the caption from the U.S. Air Force:
Major Murrit H. Davis, Commander of the 39th Fighter-Interceptor Squadron in “Sexy Sally II” and another F-51 of the 18th Fighter-Bomber Wing (probably piloted by Captain Alphonzo T. Wagner), make a successful low-level napalm run over P’yongyang, north Korea on the morning of 14 August 1951. In this famous photograph from the Korean War, two napalm fire bombs head towards their targets just a split second after being released from shackles beneath Sexy Sally’s wing. Maj Murrit was killed in action that day flying F-51D 44-74035 while searching for two other pilots shot down on the Pyongyang mission. His remains have not been recovered. (Caption adapted from original at Truckbusters from Dogpatch, USAF photo)
And here’s a restored 1943 model:
The CT-6 above was for sale in the Netherlands; here’s a clip of it driving around:
These things made it all around the world. Here’s an online forum of people from Belgium, the UK, the Netherlands, Australia, and New Zealand talking about their Clark CT-6 tugs, all of which undoubtedly were transported by the U.S. during World War II.
Someone named John Norris wrote a great history of the Clarktor CT-6 on a site named Military Trader Vehicles. Here are a few quotes describing Clark’s involvement in World War II:
As early as 1941, the Clark company was already producing around 90 percent of the military requirement for heavy-lift equipment, including forklift trucks and tow tractors. By the end of the war in 1945, it was said that there was not an Allied airfield in America, Britain or Europe which did not have a Clark vehicle on it. Throughout the war the company continued to produce new cargo handling vehicles, such as the “Planeloader” in 1943. This was the first purpose-built forklift designed specifically for use by the military in remote locations where the terrain was rough and temperatures could be extreme. These would more than prove their worth on the airfields constructed by the US Naval Construction units, known as “Seabees”, on the remote islands across the Pacific during the “Island Hopping” campaign.
[..]
The “Clarktor 6” was … known for its compact size and was developed for use on airfields as an aircraft tug. The Clarktor 6, with a wheelbase of four feet and eleven inches, was powered by a water-cooled Chrysler six-cylinder 230-cid flathead gasoline engine of 6 2hp, with a three-speed “crash” gearbox that could reach a maximum speed of 15 mph. Production began in 1942, and by the end of the war Clark had delivered thousands of different cargo handling vehicles, including an order for more than 1,500 Clarktor 6s for the British Royal Air Force. These were built as a version designated “BH”, standing for ‘British Heavy’, and supplied to Ministry of War Transport for the RAF under the Lend Lease Act.
The Clarktor CT-6 morphed over the years, with the Model-E being the “The most popular of all Clarks now in service.,” according to Keystone Ground Support Inc., a company that sells parts for Ground Support Equipment. The Model-E, built from the late 1970s to mid 1980s, looks like this:
You might see some Clark Model-Es at airports these days, or you might see a CT-30/40/50. Here’s a service manual for a bunch of Clarktor models; the date hand-written on the cover is March, 1967:
You can see that these vehicles had L-head engines built by military engine-manufacturer Continental (who also built engines for the 1958 Willys FC-170 that I used to own) attached to manual transmissions that supplemented a traditional clutch disc with a fluid coupling.
You’ll also notice that the big plate of steel on the front of these Clarktors is called “Bumper Plates,” and they’re half an inch thick!
Clark offered a number of different models, with diesel or gas engines, with manual or automatic transmissions. One thing I found interesting when going through the user manuals were these comic-like operating instructions:
Also interesting is the answer to the question you were probably all wondering: “What exactly is it about these trucks that makes them good for towing?” The engines are definitely long-stroke, and therefore make good torque. But beyond that, it’s the gearing — and not in the transmission. Check this out:
The transmission’s first gear ratio is a fairly standard 3.7:1, but that rear axle ratio: Wow — 17.311 to 1!
A typical hard-core rock crawler will have maybe a 5.38:1 axle. To have three times that axle ratio is incredible. Combine that with a fluid coupling that reduces shock loads and presumably offers further torque multiplication, and you end up with a low-speed (up to about 15 mph) tugging beast!
The Clarktors were around from 1927 until the mid 1980s, and though some are still in service, they aren’t the only luggage-tugs you’ll see at an airport. In fact, at LAX the tugs I saw were from Harlan, a Kansas City-based company that started by renting out and fixing forklifts, and then decided to build its own version of the Clarkstor. From Harlan’s website:
In 1962 Mr. Kaplan founded Harlan Corporation to rent and rebuild lift trucks. While repairing these lift trucks, Jim analyzed the causes of component failure, and found that high failure parts were not available. So, he redesigned the parts, developed sources for new designs, and bought the parts to repair his customers’ lift trucks. He then went to the Lift Truck OEM and offered to sell the improved designs. At that time, the Lift Truck OEM was not interested, but later implemented these design improvements. This drive to reengineer components, to improve reliability and reduce costs, is at the heart of Harlan’s operations today.
Soon, Jim was selling parts all over the world. In the process, he developed lifelong friendships in over 70 countries, with both customers and suppliers. Harlan’s key supplier relationships are a strength built over a 35 year period. During this time, the business was growing rapidly, driven by development of improved forklift parts for a global market.
In 1968, a customer in Venezuela asked Mr. Kaplan to make towing tractors. So, Jim went out, bought a Model E Clark, and reengineered it. Harlan Corp. had all of the required parts in surplus inventory. The first twenty-five (25) tractors took two months to design and produce, since they only required the development and production of the frame to prepare for final assembly.
Here’s a closer look at a Harlan luggage-tractor:
There is a roofed-version, in case you’re curious:
Another brand that offers luggage-tractors is TUG, which is actually quite popular today. These vehicles even more like that Clarkstor first shown way back in 1927:
Here’s a bit of history on TUG via aviationpros.com:
1973 – TUG Manufacturing Corp. is founded. Core business begins with production of baggage tractors, primarily the Model MA, which is still produced today. TELL story of tug at Museum. Tug eventually expands its product line and introduces its Model 660 belt loader. In 1998, Stewart & Stevenson buys the company and becomes known as S&S TUG. The combination of TUG and S&S’ airport division provides the GSE industry its broadest product line. S&S TUG then merges with Davco Industries, a specialist in regional airline equipment broadening the line further.
After an ownership change in 2005, TUG’s name is changed to TUG Technologies Corp.
In September 2009, TUG donated a restored Tug Serial No. 001 to the Musuem of Commercial Aviation, Forest Park, GA. The company’s first tractor was delivered to Epps Airport Service at Peachtree-DeKalb Airport on Oct. 8, 1973. Realizing the importance of keeping this part of its history, TUG bought the tractor from Key On Ground Services in Clearwater, FL.
It’s actually quite incredible that the formula remained essentially the same for an entire century!
Now that I’ve gone down this deep rabbit-hole researching this article, I really want one. Lucky for me, I found this for sale on eBay!:
It even comes with luggage trailers!
Sweet, it’d be like a bunch of rolling cabanas
Congratulations to the Clarktor for coming in 2nd place for all things Clark. In 1917 David Clark invented the Clark Bar the first successful combination Candy Bar. It was popular during WWI and WWII and all years without wars. Still being made today by the Boyer Candy Company and has a famous bar/tavern named after it. It can also be carried around in your pocket, something the Clarktor has yet to accomplish. JK
Now I want one of those too, thanks.
They are cheaper too.
Heh, I kept saying I was doing the Lemons Rally in a stolen airport tug until I knew which rental I’d end up with.
Then I started calling the rented 530e a Rolls-Royce 5er Hybrid Royale Brougham stolen airport tug, or something to that effect.
Ah, so David living in this tractor for a week is the secret reward if we hit the stretch goal of 1000 new members this month.
Come for the weird and stay for the articles.
Sorry, David. Time for your daily dose of pedantry. That Tructractor looks mid-engined to me. Also looks like it could be 4WD.
One thing I’ve learned on IMCDb, when it comes to specialized equipment there’s always more competition then you’d think. So many different brands of these. They’re fun to try and identify.
Ten-or-so years ago I worked for a company that included the Washington airports authority as a client. At National I got a good up-close look at an old Cochran belt loader with a Ford inline-6. Mid-engined, open driving position, and a low center of gravity (with the belt stowed) – practically a race car.
Off to YVR for an adventure in the Los Angeles of Canada, eh? Hope you make it to Kintaro Ramen.
Did anyone else wince at the 10 second mark of the Netherlands video clip? I could not stop thinking about what would happen if that little French Bulldog decided to take a little hop into the path of the tires spinning below.
I’d daily it.
Refit those trailers like sleeper cars with beds and other amenities — maybe add a few more trailers with kitchen and bath facilities — and you’ve got the Autopian road train. Oh, it’ll be slow, but there’s probably no obstacle it won’t grind its way over. You’ll just have to budget more travel time. Why be in such a hurry?
I bet the Changli would even fit on a trailer for local use at the destination, kind of like the moped that rides on the back of RVs.
You’d be shocked to see how many pieces of GSE use normal US-Big-3 engines. Ford 300’s seem to be the most popular.
Ford used to sell a lot of industrial engines, and the Ford 300 is extremely well suited to applications like this. It does not surprise me that they are common.
It’s the same because simpler is better. Can you imagine if it was some complex contraption DRM’d by John Deere? Air travel would be a nightmare. This can be fixed by a toddler.
Aircraft service vehicles are some of the oddest. Machines for moving aircraft can be even weirder like seaplane tugs that use backwards pickup cabs and the APC from Aliens which was an aircraft tug in disguise
BTW those extra thick bumper pieces are primarily ballast, the other ingredient for successful towing
Yes! I was hoping the Aliens APC would be mentioned in the article.
I actually have one of these that a military surplus store was selling locally. It was built in 81 and has the Ford 300 inline 6 in it. I use it for moving the miriad of project cars and as a secondary tractor. It has been pretty cool for what I got it for, but really not an everyday use item. I can also vouch you can push about anything with that front end.
Of course someone here has one!
Does it have any suspension? The picture of the 1917 Tructractor shows leaf springs, but, being designed for low-speed use on tarmac, I’m curious if it’s like an old tractor (the Ford 8N is my only frame of reference: the sole ‘suspension’ it had was the seat mount consisting of a ‘C’ of spring steel)
Sorry for the late reply, was out of town. Yes, there are leaf springs, but with the overall weight it is still a rough ride. I bought it on a lark, but it has proven useful.
Got very proficient at maneuvering the Tug version of this truck when I started at the package delivery company I still work at.
I believe ours are limited to the lowest gear only to limit speeds on the ramp.
One of the best skills to master on these things is the stop-beep-start tap dance at ramp stop signs as you’re required to come to a full stop and sound the horn (foot operated!) before proceeding.
It’s important to note that these “trucks” are very heavy and can be turned over if you drive them overly aggressively. Drivers have been killed.
When I worked the line at the local airport, we had a lowboy tug from the 40’s that still rocked a flat-head 6 of some brand. This ran like a top. I think the newest one at the airport was made in the 70’s. So easy to work on. I miss that job.
David, BUY IT!
Retrofit the baggage cars with seats and take Cali tourists on tours
Better yet. Just think of all the spare parts he could haul out of the salvage yards with one of these babies and the tug carts.
He could literally clean out an entire acre of Jeep parts in one afternoon.
Give it a Galpin livery and use it around the various lots.
Get two and race ’em!!
After the article, I can confidently state that this is a truck.
Yes!
Thank you for the confirmation! 🙂
(I mentioned things-that-tow in the comments on Jason’s truck-defining article)
This article is yet another example of why I love this website! Good job David!
(And for the record, I’ve always wanted a “tug” to remove those stubborn Dandelion roots!) 😉
It never fails to amaze me what can be accomplished by steep gearing.
“Give me a lever long enough and I could move the world.”
What is a gear but a series of spicy levers?
Yeah, it’s indeed all about the gearing. Like, there’s a kinetic sculptor, Arthur Ganson, who made a sculpture using an electric motor to turn a series of gears with the final gear embedded in a block of concrete where the gear reduction is such that it’ll take some 13.7 billion years for the final gear to turn once.
https://www.exploratorium.edu/sites/default/files/Machine-Concrete-Ganson960x453_0.jpg
Go down the rabbit hole of Predator 212 swaps on YouTube and you’ll be even more amazed. I once saw somebody 212 swap a good size tractor and gear it extremely low. He then pulled some large stumps with it, and found that he was traction limited rather than power limited. With a 6.5hp engine!
Interestingly, this is also why torque is not as important as some people think. Yeah your Cummins makes 1000lbft of torque, but so does a Honda Civic through a 5:1 reduction.
This is proven time and time again by Toyota guys with weeny 22r engines out pulling eight cylinder rigs through the magic of 4.56(or shorter) axle gears.
One factory I worked at had an old Pettibone Tug, 300 Ford I6 powered.
Fantastic article!!!
Proves that the perfectly designed tool is timeless.
“Hey look!!! I see a hammer in Lowe’s that looks exactly like the one Romans used in biblical times. Its design hasn’t changed in 2,000 years”
Incidentally, Clark is currently owned by Young-An Hat Company, the same parent company as Zyle Daewoo, one of the last two motor vehicle manufacturers still using the Daewoo trademark (Tata Daewoo being the other)
Now I want one.