Which 1840s British investment boom collapsed in the railway crash of 1847?

The 1840s British investment boom that collapsed in the railway crash of 1847 was called Railway Mania.

Railway Mania was a speculative surge in British railway company promotion and share buying, especially during the mid-1840s. Parliament authorized a large number of new railway projects, and investors hoped that rapidly expanding rail networks would produce substantial profits.

Many proposed lines required enormous capital and had uncertain commercial prospects. As interest rates rose and confidence weakened, railway shares fell. The financial pressure contributed to the broader Panic of 1847, which affected banks, merchants, and companies across Britain.

The boom nevertheless left a lasting physical legacy. Britain built major railway routes that transformed transport, communications, trade, commuting, and tourism. Railway Mania should not be confused with the South Sea Bubble of 1720 or the Dutch Tulip Mania: those were different speculative episodes involving different assets and periods.