Britain's worse tunnel fire occurred on the early morning of 20 December 1984 (NCE 3 January 1985). A goods train carrying more than 1,000t of four star petrol in 13 tankers was passing through the Summit tunnel near Manchester when a defective axle bearing caused a mass derailment. One tanker toppled over and split open.
Explosions began, and two of the tankers actually melted away.
In all, nearly 1M litres of petrol burnt for four days. Despite this, engineers carrying out inspections later discovered little serious damage to the brick lining. This was attributed to combustion products escaping up ventilation shafts. Only 500m of track and sleepers needed replacing.