Complex sentence: Several examples were rebuilt with cut-down cabs for working on the Burry Port & Gwendraeth Valley Line as there were several low bridges on the line, which normal height locomotives would not be able to clear without incident.
Split into simpler sentences: Several examples were rebuilt with cut-down cabs for working on the Burry Port & Gwendraeth Valley Line. This was due to several low bridges on the line, which normal height locomotives would not be able to clear without incident.