The 1840s British speculative boom in railway shares was called Railway Mania before its crash.
Britain experienced a huge expansion of railway promotion between 1844 and 1846. Parliament approved hundreds of proposed lines, and investors bought shares expecting railways to transform transportation and produce substantial profits. Many projects were poorly planned, overcapitalized, or aimed at routes that could not support the expected traffic.
The Bank of England raised interest rates in 1845, making borrowing more expensive and reducing the flow of speculative money. Share prices then weakened, construction companies failed, and investors suffered heavy losses. The downturn damaged the broader economy and left many approved railways unfinished or financially troubled.
Railway Mania is sometimes confused with Canal Mania, an earlier British transport speculation. The railway boom also had a lasting physical legacy: despite the crash, many important rail lines were built and became part of Britain’s modern transport network.