Complex sentence: Before nationalisation in 1948, government-backed fuel trials were made in anticipation of a post-war coal shortage and No.1831 was converted to oil burning in 1947, but reverted to coal-firing when the crisis failed to materialise.
Split into simpler sentences: Before nationalisation in 1948, government-backed fuel trials were made in anticipation of post-war coal shortages and No.1831 was converted to oil burning in 1947. Haresnape, section: "N class" This was reverted to coal-firing when the crisis failed to materialise.