The Field-Marshalls were a range of British

United Kingdom

The United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages...

 farm tractors

Tractor

A tractor is a vehicle specifically designed to deliver a high tractive effort at slow speeds, for the purposes of hauling a trailer or machinery used in agriculture or construction...

 manufactured by Marshall, Sons & Co.

Marshall, Sons & Co.

-External links:* – at the Powerhouse Museum, Sydney, Australia...

 of Gainsborough, Lincolnshire

Gainsborough, Lincolnshire

Gainsborough is a town 15 miles north-west of Lincoln on the River Trent within the West Lindsey district of Lincolnshire, England. At one time it served as an important port with trade downstream to Hull, and was the most inland in England, being more than 55 miles from the North...

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Field-Marshalls were in production from 1945 to 1957. However, the first single-cylinder Marshall came into production in 1930.
The first single-cylinder Marshall tractor to be introduced was the Marshall 15/30 in 1930. It had a bore of 8 inches with a 10 inch stroke and the maximum r.p.m.