A thief made off with a cash box from the top station on Sunday night after two other men distracted the female member of staff, its owner said.
Director of the railway, Dr Malvern Tipping, said the worker then managed to lock the accomplices in one of the carriages when it was sent halfway down the tracks.
But they escaped by clambering out and up the tracks and jumping over some railings.
Police were today trying to locate the men who were caught on CCTV at around 8pm on Sunday, just before closing time.
Dr Tipping said: "It was only a small amount of money as we do not keep lots of cash in the station overnight.
"However, the member of staff was clearly shaken by the event, but other than that no-one was seriously injured."
"But we would ask anyone who recognises these men to get in contact with the police straight away so they can be caught."
Dr Tipping is not impressed by police response times.
"The cliff railway staff member stopped the carriage halfway down the track so she could wait for the police," he said. However, the police still had not arrived by the following morning."
"Had the thieves not escaped, they would have had a long wait.
"If this is what fast response units mean as Shropshire's police stations are wound down, it does not bode very well for the future safety and security of local residents.
"Our staff have joked that the two men will probably be covered in grease in having made their escape along the track."
CCTV shows one man entering the top station. He then had a look around then leaves shortly afterwards.
A few minutes later two other men entered the station and buy a train ticket for the railway.
They then get into the carriage and asked the female member of staff to take a picture of them before the start of their journey.
At that point the first man re-enters the building and is seen taking the blue cash box from the kiosk.
It contained a small amount of cash, a set of keys and a mobile phone. The staff member then hears the door slam shut and she returns to the kiosk.
It was then she realised the cash box was missing.
She stopped the carriage halfway down the track with the two men still inside while she waited for the police to arrive.
But It was at this point the men were able to unlock the door and scramble up the track.
They then confronted the female member of staff for locking them in the carriage, before making off in the direction of Castle Walk.
Chris Preece, general manager at the station, said CCTV images which staff believe show the theft in process have been handed to police. He said: "Our CCTV images are so clear . . . and I would recommend high definition CCTV as these three man can be seen clearly. I would also like to point out that if anyone else tries to do something similar, we would be able to get their faces clearly on CCTV."
Information to police on 101.