Complex sentence: In the 1860s and early 1870s the line was of great importance being the direct route from London to Glasgow, before the Shap route was opened passengers (allegedly including Queen Victoria) would travel from Euston to Fleetwood and then onwards via steamer to Scotland.
Split into simpler sentences: In the 1860s and early 1870s the line was of great importance being the direct route from London to Glasgow. Before the Shap route was opened, passengers (allegedly including Queen Victoria) would travel from Euston to Fleetwood and then onwards via steamer to Scotland.