WW II M4 High Speed Tractor and 155-mm Gun

One of the vehicles that was of interest to me was the M4 High Speed Tractor. Early on I bought the Nitto Kit, but was not able to build it. A few years ago Hobby Boss produced some fine kits of both versions of the M4. And as you can guess I bought both of them. I always pictured this vehicle with a 155-mm Long Tom in tow on a diorama. Long time only the AFV Club version was available as was the Verlinden version. AFV Clubs version though was the post WW II version and was not suitable for my project. And the Verlinden one lacked the limber. Oh well I think nothing goes as you want it to be. But recently AFV Club produced some fine models of the Long Tom en its brother the 8-inch Gun. Both in WW II version and with the correct limbers. So now I can build it as I planned. Below I give more information on both the M4 HST as on the 155-mm Long Tom.


The M4 High Speed tractor was of the crawler or track-laying type and could be used for either highway or cross-country travel even under the difficult operating conditions provided by mountains, swamps, sand, or where it was necessary to cross small unbridged trenches. It had 3 forward speeds and 1 reverse speed, and because of its relatively low center of gravity, the tractor could easily climb slopes which might have been as steep as 30 degrees, depending on the kind of footing available and the load being pulled. Note that the High Speed Tractor is mentioned as the Medium Tractor in the manual. There were also two versions that differd by the fitting of the ammunition boxes at the rear that were interchangeble.

Below the top view on the left showing the vehicle from the rear to the front. On the right the bottom view with all the panels shown from front to rear.

As mentioned in the text. A comparison of the M4 for the 155mm gun and 8in howitzer above left, and the 90mm anti-aircraft gun on the right. The vehicle on the left is from the early production run with ventilation panels on the side of the ammunition box. Below both vehicles viewed from the rear.

As I'm building the version of the M4 with the Long Tom I'm showing the appropriate stowage box below.

In the following pictures the M4 HST is shown with de ammunition box for the 155-mm shells.

For both versions of the M4 ower was supplied by a 6-cylinder, water-cooled, 4-cycle, valve-in-head, gasoline engine produced by Waukesha with a maximum rated horse- power of 225 at 2,100 revolutions per minute.


o. Steering. Steering is accomplished by means of a controlled dif-
ferential. The action is controlled by means of brakes and hand levers.
d. Seats. The cab is divided into 2 compartments, with seating room
for the driver and 2 men in the front compartment and double seats in
the rear compartment accommodating 8 men. The cushions are canvas
zipper bags padded with blankets. Back cushions are leather covered.
e. Equipment. Equipment on the tractor includes batteries and elec-
trical ignition and lighting system, electric starting motor and generator,
speedometer and engine tachometer, fire extinguisher, electric and air
trailer brake controls, and winch. A gun ring in top of cab provides for
mounting of a 30-mm or 50-mm machine gun, and an ammunition box on
rear provides for carrying of 90-mm or 155-mm ammunition. Tools are
carried in a box on left side fender.

Below two views of the M4 HST with Long Tom during trials.

The Models and Materials needed
Building The Models

The Final Result





Where to find information