Possible Clues:

• Drivers, one prevaricating about vehicle on track
• Protest about a king's means of transport
• Training wheels?
• Complain bitterly about extremely dear carriage from US
• Storyteller upset by most of the care taken by passengers
• Trolley, e.g
• Coach working on American lines
• There's no end of bother behind bar in American's carriage
• Track team member?
• Track roller