Dennis is a diesel shunter.
Dennis was mentioned by Andy.
Dennis delivers Connor's new tender to the Mahrington Works. He asks Connor for his thoughts, but cuts him off, saying he doesn't care, then leaves.
Not much is known about Dennis. He has been known to be lazy in the past and try to get out of doing work. However, the events of the Locomotive War changed him.
• Personal Game (mentioned)
- Dennis is the third diesel in the series not to be voiced by Nick.