Possible Clues:

• Scotty's position
• Train VIP
• Contact him if the motor starts to hesitate
• Bring about, being skilled in machinery
• One who designs, makes or runs motors
• Contrive finish (not start) without drink
• Person in charge of building bridges, etc.
• Would a drink at last ever make one mechanical?
• Person who uses scientific knowledge to solve practical problems
• Would in the end spirits ever help him keep things going?