An Entertaining & Informative Vintage Automobile Internet Magazine

A 1914 Knox-Martin Tractor – “The Tugboat of Land Commerce”

  • Members of the Boston Fire Department inspect a new Knox-Martin tractor coupled to a formerly horse-drawn steam pumper.

This big Knox is a prime example of why we like pre-war vehicles so much. It’s unusual design might look quite odd to modern eyes, but it typifies the innovative thinking of the era. The tractor was powered by a water cooled 432 c. i. overhead valve 40 horse power four cylinder engine, which may have been similar to the Knox cars of the era. The single front wheel’s ability to turn to almost a full 90º in either direction allowed for a very tight turning circle, a decided advantage when maneuvering through the narrow streets of old Boston.

It is clearly a conversion of a horse drawn apparatus, as was this Christie powered unit. A second seat with button-tufted upholstery, quite visible in front of the pressure dome on the trailer, is the perch from which the horse team was driven. You can also see two other Martin tractors here on The Old Motor. Our feature photo is courtesy of the Leslie Jones Collection at the Boston Public Library.

  • L to R : An article in the November, 1913 Automobile Trade Journal about the 1914 model. The Motor of February, 1912 describes some unique design features. An an illustration  from the January 18, 1913 issue of  “Automobile Topics”.

An interesting and graphic ad from the May, 1913 issue of  “The Motor Age” (below) shows one of the many types of trailers used with Knox-Martin tractors for heavy haulage.

4 responses to “A 1914 Knox-Martin Tractor – “The Tugboat of Land Commerce”

  1. The Martin tractor was devised by Charles H. Martin who invented the “fifth wheel” trailer coupling in 1911. The three-wheeled Knox was among the earliest vehicles to adopt the invention (which ironically made his “fifth wheel” the fourth wheel on the tractor). He founded the Martin Rocking Fifth Wheel Co., in Springfield, Mass., and then founded the Martin Motor Company, through which he introduced the three-wheel Scootamobile in 1921. The Scootamobile was a 150-pound, two-passenger aluminum-bodied car capable of delivering gasoline economy of 75 miles per gallon and 40 miles per hour. At least four different Scootamobile prototypes were produced, all with two wheels on the driver’s side and a single wheel on the passenger’s side. They were powered by a Henderson vee-twin motorcycle engine. The cars rolled on cast aluminum wheels without axles or universal joints. The work of Charles H. Martin is often mistakenly credited to James V. Martin, whose little Martin Dart cars of 1926-30 also used cast aluminum wheels without axles or universal joints, but the two ventures were unrelated. You can see the Dart elsewhere on

Leave a Reply

Your email address will not be published. Required fields are marked *