Why Walking Tanks Never Became A Thing

The walking tank concept has always captured imaginations. Whether you’re talking about the AT-AT walkers of Star Wars, or the Dreadnoughts from Warhammer 40,000, they are often portrayed in fiction as mighty and capable foes on the battlefield. These legged behemoths ideally combine the firepower and defense of traditional tanks with the versatility of a legged walking frame.

Despite their futuristic allure, walking tanks never found a practical military application. Let’s take a look at why tracks still rule, and why walking combat machines are going to remain firmly in the realm of fiction for the foreseeable future.

A Flawed Concept

The AT-AT Walkers from Star Wars are intimidating to the uninitiated. Fundamentally, though, they present a huge target to the enemy and are incredibly slow moving. Furthermore, destroying just one leg is enough to take down the entire machine.

World War I saw the dawn of the tank, which quickly proved to be a game-changer on the battlefield. The huge tracked machines offered an excellent way to break stalemates in trench warfare. Tanks had big cannons and machine guns that could blast away fortifications and unprotected troops alike, while they offered significant protection against small arms fire for the crew inside. They also the ability to progress through soft, muddy terrain by virtue of the low ground pressure created by using tracks instead of wheels.

Tanks, however, have their drawbacks. They’re not always great at dealing with obstacles or highly uneven terrain. Relatively simple fortifications like dragon’s teeth can easily stop a tank push, while potentially presenting little difficulty for a walking machine to deal with.  For dense, obstacle-ridden areas, like forests or mountain paths, it’s easy to imagine the value of a walking tank that could step over things that would frustrate a modern tank.

Realistically, walking tanks would have a plethora of vulnerabilities in combat scenarios. Intricate leg mechanisms would make them highly susceptible to damage from enemy fire. Furthermore, any hits to a leg would leave the machine potentially unbalanced, or cause it to tip over. It happened in MechWarrior, and it would happen in real life, too. Blow a leg off, and you’ve got an easy mission kill. In comparison, blow off a tank track, and the vehicle remains upright and generally relatively repairable.

Remove the legs and replace them with tracks, and you’d have a vehicle with a much lower profile and better survivability. Sure, it couldn’t step on a small house, but when has that ever proven useful in combat?

The walking form factor also presents other problems. Besides sheer mechanical complexity and maintenance concerns, it’s difficult to imagine a walking tank that could be anywhere near as low to the ground as a modern main battle tank. Modern designs aim to be as low profile as possible to make them difficult to engage. An ungainly tall walker could readily be spotted and fired upon at a much greater distance than a low-slung tank that can more easily use terrain as cover.

With the emergence of aerial warfare, precision weaponry, and advanced anti-tank weapons, modern ground units benefit greatly from high mobility. Indeed, the value of speed to mechanized combat has been obvious since World War II. Not only would a walking tank struggle to maneuver quickly to respond to enemy fire, it would struggle to keep up with a modern army consisting of regular tanks, armored personnel carriers, and trucks. At best, one could imagine a walking tank maybe achieving a “jog” of 10 to 20 km/h. Leaving aside the potentially horrid ride for anyone on board, that compares poorly to even the heaviest tanks currently in service. Modern designs can readily hit top speeds of 70 km/h or more.

It also bears thinking about the actual benefits conferred by a walking design. Barring certain passive anti-tank defences and such, how common are situations where a walking tank would be able to proceed where a tracked tank wouldn’t? Then, contrast that against how easy it would be to make defences that trip up a walking design. We’ll take your best answers in the comments below.

A Footnote in History

The closest the world has ever gotten to a walking tank was the GE Walking Truck. It was slow, ungainly, and incredibly taxing to operate. Credit: Mytwocents, public domain

Despite the flaws of the idea, the concept has not gone entirely ignored by the military fraternity. The frantic heights of the Cold War era actually saw the idea of a walking military vehicle explored by General Electric in the 1960s. This resulted in the GE Walking Truck, as designed by Ralph Mosher, also known as the “Cybernetic Anthropomorphous Machine” (CAM). Weighing 1,400 kilograms, it was intended to help carry equipment for infantry over rough terrain. The prototype was unarmored and unarmed, serving merely as a proof of concept.

The Walking Truck was controlled by an operator seated inside. The operator would maneuver the machine’s legs with foot and hand movements which activated hydraulic valves, controlling the limbs of the machine. It was one of the first machines to use force feedback controls to aid the operator. The walking mechanism allowed the CAM to walk across varied terrains and carry heavy loads. However, it was painfully slow, with a top speed of just eight kilometers per hour. It also suffered from high power consumption, and was mentally taxing for its operator to drive.

Despite its impressive stature, the Walking Truck was simply not a practical military vehicle. It wasn’t up to its intended task of hauling equipment, let alone serving in any sort of combat role. Even then-ancient tanks from the interwar period would thrash the Walking Truck in a speed contest.

The Walking Truck benefited from force feedback controls that helped the operator intuitively understand what its limbs were doing. This gave it great finesse, but it was mentally exhausting to operate.

Today, we have far more advanced motion control technology, sensors, and controls. Walking robots have also come a long way from the janky experiments of the 20th century. It’s easy to imagine many of the control issues being eliminated in a modern design that could automate the walking task for the operator with sensors and control loops. Regardless, the fundamental flaws of a walking platform would remain.

Indeed, Boston Dynamics would go on to to develop a range of legged robots aimed to do a similar job to the Walking Truck on a smaller scale. The BigDog prototype was eventually developed into the Legged Squad Support System, which helped explore the value of a robotic pack mule to aid dismounted soldiers on the ground. The ability of the robot to work in similar terrain to a walking soldier was of great benefit, but ultimately, the concept was deemed impractical for operational use. Concerns around repairability, control, and utility led to an end of the program in 2015.

Fiction Vs. Reality

The main battle tank concept continues to maintain its place on the battlefield for good reason.  “Firing M1A1 tank in Djibouti” by Alex C. Sauceda

The limitations of walking machines are so pervasive, it’s no surprise walking tanks have never been built nor deployed in combat. Even in the world of fiction, their limitations and ungainly nature is obvious. In as much as the AT-AT Walkers looked devastating in Star Wars, it’s easy to imagine a small cadre of modern tanks speeding into position in the snow and firing off a few rounds before the legged behemoths could even turn to face them.

The same goes for the battle mechs of MechWarrior fame. It’s hard to imagine a 14-meter tall mech surviving long when a shell impact to the head would probably topple over even the most well-armored two-legged design. Indeed, these flaws apply to just about any walking tank design you can imagine, barring near-mythical flying designs from anime that are basically another whole thing entirely.

In this real world we live in, the efficiency, ruggedness, and simplicity of regular tracked tanks reigns supreme. As foreboding as walking tanks might look in fiction, they simply would never pose a serious threat in any real combat situation.

65 thoughts on “Why Walking Tanks Never Became A Thing

  1. The advantages to be gained from a low profile would seem to not just be difficult to realise in a walking design but directly opposed to the design aims of a machine that can step over obstacles.

    Maybe a centipede-like design would have the advantages of both. Or Rincewind’s Luggage.

    1. The first wave of attack would be to just drop the relevant Discworld books over the enemy line. Give them, say, a week to read and discuss, then deploy one (1) article of luggage.

      1. Both of those are much more predictable movement/jarring than walking/running on 2 legs would be. Yes it could likely be solved, but it would be far more involved than the current methods used

  2. Hmm… a four legged walking tank is perhaps not a good idea. Shoot one leg off and it’s disabled. Therefore it is better to have 3 legged walking tanks, like the ones from “War of the worlds” the Jeff wayne version has some pretty illustrations of 3 legged walkers that seem to be indestructible.

    Now the smart comment reader might say, that shoot another leg of and it will fall down. Good point, therefore perhaps the 2 legged walking tank is better, it has no 4th leg or 3rd leg to shoot off. This concept has been proven to work in games like “Walker” on the Amiga (great shoot-m-up game, wasted many hours on it in my Youth).

    But again… shoot another leg of and it falls down. So a one legged robot perhaps? Attempts have already been made, just google it and be amazed. But a one legged hopping tank… nehh. I’ll guess a tank with no legs would be best.

    Tracks aren’t so bad, the lower the pressure on the ground, so your heavy tank doesn’t sink in the soft ground or mud. But still tracks can be shot off too, so a tank without tracks could be better. how about a hovertank, as demonstrated by SGT. Bilko, this might be a concept that might actually work… What could possibly go wrong?

    1. “This concept has been proven to work in games like “Walker” on the Amiga (great shoot-m-up game, wasted many hours on it in my Youth).”

      Lol, you made think of the 90s era ‘Walker’ animations on Amiga starring Amy the Squirrel.. 😁

  3. Then there’s David Drake’s future tank from _Hammer’s Slammers_ : take a modern tank, remove the treads and drive train, and replace it with high speed, high volume variable pitch ducted fans and armored skirts to contain the air forced into the plenum by the fans. replace the power plant with a fusion bottle, and bob’s your uncle.

    1. Wait, I remember that, the Hover Tank from Sgt Bilko!
      I remember they made a point of the main drawback of the frictionless design without even touching on the power requirement.

    2. I read the Hammer’s Slammers books in Jr. High and thought up many ways to stop them in their, uh, lack of tracks.
      First one, a concrete ditch with a grid cover that has all the holes fitted with plugs that can be blown out, covered with a layer of dirt. It holds together just long enough for a hovertank to fly over. The grid blows clear and CLANG, down goes the tank. Stuck on the grid with enough free space below it cannot create and air cushion. The tanks can go across water, so make some water that’s a trap. Carve the bottom of the moat into multiple cells containing half of a binary liquid explosive. Seal them with a membrane then flood over the top with the other half of the liquid explosive. Ideally the explosive liquids are denser than water and not water soluble so a layer of water can float on top. When a hovertank goes over, the pressure ruptures the membrane over one or more cells and BOOM, up goes a huge splash of liquid into the fans, along with the rapidly expanding combustion byproducts from the explosive. This would have a risk of one tank setting off the entire explosive moat. The gridded trench could be combined with a moat by placing the grid just beneath the water surface then rapidly draining to trap the hovertanks. Could add water cannons to fire up into the fans to wreck them. Good old mines, but with the capability to aim their blasts into the fan ducts from below, or sideways to punch holes and notches into the metal skirting to destroy their air cushion. The sideways fire could also work from outside the skirting. Double action pop up mines that launch one projectile to trigger the antipersonnel defense, followed by a second that contains an upside down missile. It has cameras and “smarts” that identify an air intake, angle the projectile then fires the upside down missile downwards into the intake to damage or destroy a fan. Lastly, the flat missile or “Flissile”. It’s low, it’s flat, it skims along just centimeters off the ground in high speed ground effect. It has wheels and a sharply angled/pointed cutting bar to punch through vegetation up to small sapling size. Its goal is to evade defensive weaponry on the hovertanks, explode through the metal skirting and set off an explosive in the air plenum. All of that I thought of around 35 years ago.

    1. There is an autobiography called Soldat by a German cavalry officer who managed to escape to America after the war, about his experience being a soldier in the German regular army. At the start of the war cavalry was all pulled by horses, and mechanized units didn’t appear for several years. This was just the current technology of the day. The US didn’t want to deal with transporting all those horses across the Atlantic, so it was worth it to us to go to the effort and expense to mechanize our cavalry. It worked so much better that other armies were forced to follow suit.

      1. Thanks for the info, the thing with the horses and panzer makes sense.
        Personally, I assume that in WK1 pride and moral still was important, too. Soldiers still had that Prussian mindset, kind of. For example, civilian enemy ships on sea had to be warned and evacuated first, before the unmanned ships were being attacked and sunk. WK2, by contrast, was much less humane. So many casualties on all sides..

      2. Sorry, but the US didn’t start mechanising its cavalry units until January 1933 (1st Cavalry). The AEF didn’t bring any cavalry with them in 1917/18 because it was obvious years earlier that cavalry was all but useless in the trench warfare that dominated the western front; the limited amount of time they had to train 2.8 million draftees also played a role.

        Tanks were introduced by the British before the US even entered the war, but were slow had very limited range. Cavalry was faster, more maneuverable, and had a greater operating range than armor, but was much more vulnerable to automatic weapons.

        US troops did not reach the front until October 1917, but in very limited numbers; I Corps wasn’t fully activated until January, 1918. What tanks they had were Renault FTs.

        Meanwhile, the first mass armor attack was at Cambrai in November 1917 by the British. So no, the other armies weren’t “forced to follow suit” – they led the way.

  4. Legs don’t offer any advantage over treads if they’re “dumb”. However in the modern day, with limbs that react intelligently to the environment, it’s possible to imagine some niche cases where a legged vehicle would be superior. One example that comes to mind is operations on steep, mountainous terrain. You often see infantry operating in these conditions with no vehicle support.

    I believe we have the technology today to make the legs somewhat intelligent in their movement. But there’s an additional problem of speed. Hydraulics are powerful, but not fast, and combat vehicle would need to be at least as fast a human to be useful.

  5. The reason for using the AT-AT is that no one expected it. Who wouldn’t want to use armored vehicles that can deal with ice and uneven terrain in a warzone that doesn’t use projectile weapons against mostly soft targets?? Sure, countermeasures are always possible but not always timely. Timing is everything and the ability to make inroads before the enemy can respond can be devastating. The innovative use of unexpected technology wins the day…usually. A landspeeder dragging a cable is just another example of an innovative use of unexpected technology.

  6. It is curious that the author acknowledges the advantage of the tracks over wheels (lower ground pressure), but does not consider that for a walking tank. Legs would have even higher ground pressure (due to their smaller footprint), so under the mass of a tank would sink even more into the terrain. This would even worse for two-legged, vertical machines. Countering that with bigger feet would take away some stability, making the feet adjustable would make it even more complicated…

  7. the AT-AT looked stupid the day the movie came. Apart from being slow, vulnerable, with a crappy offensive weapon, what about close in anti personnel support? What is in that huge volume behind the cab?

    And it looks like HaD comment system has got worse – not something I would have believed possible..

    1. There were two prototypes the one in the video thumbnail and one that’s more “prototype looking” that’s blockier and cruder in appearance. They’re moldering away in museums. What did come out of that project is the tree handling arm with the delimber and cutter. That gizmo has been widely adopted on wheeled and tracked logging equipment. AFAIK the Timberjack hexapod is old enough all the important patents should be expired.

  8. I think the AT-AT design makes a bit of sense if you consider it was probably deployed after heavy waves of tie fighter and tie bomber runs, or bombardment from space to take out heavier resistance…and the fact that the empire was likely employing it against a lot of worlds that didn’t have ion shields, wind speeders or jedi.

    On 2nd thought…it could be viewed as a nod to the military/industrial complex. Gov’t is gov’t when it comes to overpriced, over budget, cost plus weapons project, or even peaceful ones like SLS.

    Or perhaps the simplest explanation is that George Lucas and fans just aren’t weapons designers and probably didn’t really have the foggiest idea that their baby would grow into such the culture inpacting juggernaut it became.

    Now over to the GI Joe and Cobra groups to debate how they got it right or wrong. ;-)

  9. Russia has been proving the increasingly obsolescent nature of main battle tanks throughout their Ukrainian campaign. Any soldier with a reliable comms link, a map, and or accurate designator, can now call down precision ordinance on something as small as a pickup truck.

    Between drones with mortars and individual soldiers with anti-tank guided missiles… being buttoned up in a big, loud, hot, relatively slow moving target with a poor rate of fire seems like a bad idea these days. I forget the title but one of the Battletech novels follows an “anti-mech commando” who specialized in disabling the weak joints of mechs with satchel charges.

    Don’t get me wrong, Battletech is one of my favorite fictional universes and I loved the games, but I’ve whacked my shins on enough truck tow hitches to know that legs aren’t always the best option.

    1. The tank has been declared obsolete every year since 1915. If the Russian army in Ukraine is to be used as a reference for what technologies are effective, we would also be declaring the obsolescence of the truck and of artillery. Instead, it should be an example of those ideas being implemented poorly.
      Their armor didn’t work with their infantry, they created and failed to protect gigantic convoys, and they kept losing generals because they communicated their positions with mobile phones. I know this is primarily about “walking” tanks, but even then I’d say this conflict has done nothing to discredit that concept (at least, not in any new way). Also, I can’t live with the “poor rate of fire” point, because that’s a critique of cannons and ignores the fact machine guns were mounted on tanks from the very start.
      Please excuse my pedantry. “Tanks are obsolete” is one of many ideas that frustrates me with its persistence.

      1. Obsolete may be the wrong word but I can’t overlook the massive logistics burden of a 70+ ton artillery piece with maintenance requirements similar to that of a jet aircraft. Someting along the lines of 8 hours wrench time for every 1 of continuous operation. Its a very expensive solution that has spawned a plethora of cheap effective countermeasures. Never mind the fact that we can bolt a Hellfire missile to just about anything now.

        You couldn’t pay me enough to be a tanker on the modern battlefield.

        1. The Abrams is 70 tons – and the US is working hard to rebuild it to cut 10-15 off because we know its too heavy. Lot’s can be done with proper system integration rather than what we’ve been doing for 40 years – bolting new shit on.

          But it doesn’t require an 8:1 ratio of maintenance to operation. Sure, it has a ‘jet engine’ in it – but its not a jet. Even then, the high ratios of maintenance to operational hours for aircraft are *peacetime* ratios intended to prolong the service life of the aircraft, not schedules that are intended to be adhered to in times of war.

        2. Tanks work well, depending on the use case. When you need to project force against a hard target (eg, other tanks, dug in defenses, bases) then they do an excellent job. War has started to focus on asymmetrical warfare due to the success of the battle tank concept. Now lines of defense are more elastic and are expected to frequently shift. Main battle tanks will continue to be the threat and the hammer, much like the pike formation of old. They define the shape of combat, even if they may not be the primary player.

          Infantry and light cavalry will remain the primary force if only because they can react to battlefield changes faster than larger armour. Light Cav specifically may shift to small quad vehicles (tracked, wheeled, or maybe legged) which can strike hardened targets. They may be autonomous or remote or require an operator. We already see missiles mounted on ATVs; that’s essentially what I’m thinking of except smaller where possible.

          As for infantry; how big do we have to consider something to be before it can be called a tank? Battletech’s Battlesuits come to mind, as do Heavy Gears, or the walkers in a recent anime called Obsolete. All 3 options are smaller than standard MBTs but provide functions that improve a soldier’s impact. The US military when dealing with insurgent groups in the Middle East generally increased their average soldier’s loadout, not decreased. Exoskeletons are already being considered which would improve what armour and weapons a single soldier could bring to an operation.

          Boston Dynamics might have failed for now, but we’re just getting into autonomous systems use in combat. The concept of a pack horse or a walking “tanklet” that can provide heavy infantry support is possible. They won’t be 14 meters tall, but then again we already know physics won’t allow that.

    2. We don’t stop using weapons because they’re vulnerable – infantry have been able to kill tanks for almost as long as tanks have existed. Aircraft kill them. Artillery kill them.

      We use a weapon because of the *capability it brings to the battlespace*.

      Tanks still bring that capability.

      You’re looking at a narrow slice of time when a new weapon is deployed and counters are not yet – but the counters are already coming. Ukraine isn’t surprising anyone (well, except how poorly the Russian military is performing;), rather its *confirming* things we’ve already been working on.

  10. The real question is – WTF was that cable made of that the AT-AT didn’t just snap right through it and why don’t they make everything out of material that strong;)

  11. In the real world several countries actually abandoned tanks altogether.
    Not sure why. But I know they ARE costly and easily taken out with modern weapons, so it seems a bit of a waste to purchase them really.

    Did you see that IDF tank the hamas disabled? I wonder what happened, I would guess the hydraulics were done for and it became a very heavy and very big paperweight. But that would mean the hydraulics are vulnerable on that model, and that is a bit of an issue. Anyway, it’s a bit embarrassing to have a tank be disabled by people without fancy weapons (and horrible to be the crew that is captured). Same happened in Iraq though, the Iraqi took out at least one US top-of-the-line tank.

  12. Tanks are fine in the Great European Plain and the arab deserts. But a jungle/forested environment like Vietnan or central Africa or Siberia would be prime ground for a legged tank, as the tree cover mitigates sighting and a sensor pack can mitigate surprise attacks. (think the brazilian fugitive that was found using thermal imaging in a forested area, circa mid-2023 in Pennsylvania).

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