Negligence is a failure to exercise appropriate care expected to be exercised in similar circumstances.
Negligence can lead to this sort of collision: a train wreck at Gare Montparnasse in 1895.
Donoghue v Stevenson [1932] AC 562 was a landmark court decision in Scots delict law and English tort law by the House of Lords. It laid the foundation of the modern law of negligence in common law jurisdictions worldwide, as well as in Scotland, establishing general principles of the duty of care.
Gilmour Street station where Donoghue arrived in Paisley
Parliament House in Edinburgh, where the Court of Session sits
The Palace of Westminster, where five Lords of Appeal in Ordinary heard Donoghue's appeal
The 1842 Versailles rail accident Lord Tomlin referred to, in which over 70 people died when a train derailed; the cause was a broken axle.