Short answers, pulled from the story.
Railway Mania was a stock market bubble in the British railway industry in the 1840s. At its zenith in 1846, Parliament passed 263 Acts authorising new railway companies, with proposed routes totalling 9,500 miles. About a third of those authorised lines were never built.
Railway Mania was caused by a combination of falling interest rates, a recovering economy, and minimal government regulation of new companies. The repeal of the Bubble Act in 1825 allowed anyone to form a joint-stock company and sell shares for a 10% deposit. No authority capped the number of railway companies that could form or scrutinised their financial viability.
George Hudson was a railway magnate who consolidated routes across the North and Midlands of England by amalgamating smaller companies. He served as a Member of Parliament while leading this expansion. He ultimately failed when it came to light that he had paid dividends to investors from their own capital rather than from actual railway earnings.
Railway Mania ended after the Bank of England raised interest rates in late 1845, drawing capital back toward government bonds. Share prices fell and investment stopped virtually overnight, leaving companies without funding. Many middle-class families who had committed their entire savings to new railway companies lost everything.
A total of 6,220 miles of railway line were built from projects authorised between 1844 and 1846. Practical lines included the initial section of the Great Northern Railway and the trans-Pennine Woodhead route, along with large parts of what became the North Eastern Railway. The entire modern UK railway network is around 11,000 miles.
Railway Mania is often compared to the telecom and internet investment booms of the 1990s and early 2000s. The dot-com bubble collapsed in 2000, and the telecoms bubble burst in 2002 with the bankruptcies of Enron, WorldCom, Global Crossing, and QWest. In 2025, analysts also drew comparisons between railway investment and the boom in AI data centres.