|Position||Arlesdale Railway diesel|
|Age|| 89 (as of 2018)
Built in 1929
|Arrived on Sodor||1967 or 1968|
Frank and Jock were meant to appear originally in the Season 3 episode, Tenders and Trouble. The story features Bert having someone else's tender due to The Small Controller's emergency of a landslide that blocked one of the railway lines down from the station. A ceremony at the end reveals that Jock is the engine that has the tender and unfortunately, this episode has been cancelled by WildNorWester.
Frank is voiced by Matthew Gamble, who previously voiced an engine Driver for Sheffield in Ruffled Feathers. When Mike got close to the chute at Arlesburgh West, Frank who was shunting some vans stopped in the middle to prevent a collision and told his driver to change the points. A quick-thinking workman changed the points and Mike was on top of the chute. Sheffield later rescued him by using a truck of sand as a barrier to prevent further damage to his front buffer beam. He survived by landing in the sand and Sheffield's driver switched off the steam that was hissing from Mike's wheels.
Frank came to the main depot to find a new engine on the flatbed that was shunted by Douglas early one morning. He returned from his job, but wasn't feeling well due to his overheated engine. He talked to The Small Controller and Olivia about this new engine. He participated in hauling Olivia to the new tracks on the Arlesdale Railway. Frank was in the shed when both Mike and Olivia left the main station on his passenger run. Frank then took a works train in the sunset to the extension line where some points were broken. Frank's engine banged so loud and he was exhausted before a workman said about fixing the extension line to his driver.
Frank's predicament reached the passenger train, while the only thing left was to get him out of the area. Frank was rescued and taken along the line to the station when a voice came from an old mill that was turned into a museum. He talked to Olivia from his breakdown scene to the station scene with The Small Controller. Frank spoke about Olivia's first day on the railway during the evening with her, Rex and Mike.
Frank is based off the Ravenglass and Eskdale Railway's Perkins built in 1929.
- Season 4 - One Good Deed (mentioned)
- Season 5 - Sheffield's Secret
- Season 1 STMY - Rough Start and Cold Reception (does not speak)
- Season 2 STMY - Food for Thought (does not speak) and Storm Damage
- For his appearance(s) in STMY, Frank was commissioned to Sean O'Connor of SI3D, as WNW was only making Mike, Rex, Bert, and Jock. However, the model was not ready for "Rough Start", so a model from the Crovan's Gate Works website was used as a stand-in. The model was finally completed in 2016, and publicly showcased on May 5 of the same year.
- Frank's newest model shares the same faces as Winston and Caden.