Complex sentence: The wagons arrived at Newport Workshops as "JSX", but were repainted and released to traffic as "JSF" s. Some official records indicate that they were supposed to have been released as "JSX" and renumbered later.
Split into simpler sentences: The wagons arrived at Newport Workshops as JSX, but were repainted and released to traffic as JSF's. Interestingly, some official records indicate that they were supposed to have been released as JSX and renumbered later.