Thomas first encountered Lucas & Lucien in a siding at Rockface Station Yard, where they thought there was an emergency after Thomas woke them up. Annie and Clarabel then explained to him what they were for. He later collected them after Ryouma' accident with some trucks.
After Kelsey arrived and the Search and Rescue Centre was built, Lucas & Lucien became obsolete. They remained on their siding at Rockface for several years, eventually being noticed by Koh. Looking for a change in scenery, they had him take them to Timbertown Harbour. However, the sea air caused their gears to not work properly, so they asked Oliver, who was passing by, to move them somewhere else. He took them to a field on the Little Western, but they quickly grew bored there. When Brody passed by, they asked him to move them somewhere else, so he took them to the Light Blue Mountain Quarry. However, Daisy soon derailed on the other side of the island from the Search and Rescue Centre and Lucas & Lucien were missing, meaning that Thomas would have to go all the way to the Search and Rescue Centre from Rockface to get Kelsey. However, Brody was able to track them down and bring them to Daisy. Happy to be useful again, Lucas & Lucien were taken to Timbertown that night. The Muscle Controller then decided to relocate them to Timbertown permanently, allowing them to handle emergencies on the west side of the island while Kelsey handled the east, having realised the strategic importance of having more than one breakdown train.
When Henry had an accident at Vicarstown on the viaduct, while taking a goods train to the Mainland, Edward took Lucas & Lucien to the accident scene that evening, where they lifted Henry back to safety. After that they were left on their siding at Rockface again.
Lucas & Lucien are both heavy sleepers, but take their jobs very seriously, usually only awaking if there is an emergency (or if they think there is). The two also seem to be very talkative. They are always ready for an emergency and respond with zeal and vigour and enjoy working.
Lucas & Lucien are painted Red with yellow hazard stripes along their sides. They have brass nameplates on the sides of their cabs.
- Series 20 - Mucking About and The Missing Breakdown Train
- Series 21 - Springtime for Diesel and Daisy's Perfect Christmas
- Series 22 - School of Brody
- Series 23 - Chucklesome Trucks (cameo)
- Journey Beyond Sodor - Somebody Has to be the Favourite (cameo) and I Want to Go Home (cameo)
- Series 21 - Set Friendship in Motion (Jerome only), Doing it Right and Little Engines
- Series 22 - All the Girls Around the World and The Steam Team
- Aside from the addition of faces and nameplates, Lucas & Lucien differ slightly in design from the original incarnation of the Breakdown Train:
- The cable to raise and lower their crane arms was moved to their roofs, rather than being attached to a smaller arm.
- Their cabs are slightly taller and their crane mechanisms are slightly shorter to accommodate faces.
They have yellow hazard stripes, which were originally not present.
- Judy is the first female crane in the series.
- Even though they now live in Timbentowm Yard as of the twentieth series, they were seen in their siding at Rockface again in Made in Berk.