Fox joined the Associated Society of Locomotive Engineers and Firemen in 1886 and for a number of years was ASLEF Branch Secretary at Mexborough, Yorkshire.

[3] In September 1901 ASLEF's General Secretary, Thomas Sunter, died in office[4] and in December Fox was one of 10 candidates in the ballot to succeed him.

[11] In 1903 ASLEF affiliated to the Labour Representation Committee[7] and in the 1906 General Election Fox was the LRC candidate for Leeds South.

[12] He polled 4,030 votes,[12] losing to the Liberal incumbent Sir John Lawson Walton, and in 1921 ASLEF's official historian blamed "a strong A.S.R.S.

[14] When the Liberal candidate William Middlebrook won, Fox blamed opponents for exploiting the division between railway unions.