Original: The first electric passenger trains ran in 1914, on the West London Line route (Willesden to Earls Court), and full services over the whole network did not commence until 1922, work having been delayed by the First World War.
Simplified: The first electric passenger trains ran in 1914, limited to the West London Line route (Willesden to Earls Court), and full services over the whole network did not commence until 1922, work having been delayed by the First World War.