Complex sentence: The first locomotive, "Lancashire Witch" was built by George and Robert Stephenson; originally intended for the L&MR it was delivered temporarily to the B&LR as it opened first, and later returned to the L&MR for use in its construction.
Split into simpler sentences: The first locomotive, "Lancashire Witch" was built by George and Robert Stephenson. It was originally intended for the L&MR but was delivered temporarily to the B&LR as it opened first, and later moved to the L&MR for use in its construction.