The Scottish Railway Preservation Society in Bo’ness was this week counting the cost of the theft of four specially-cast brass axle boxes, totalling around £10,000.
The charitable body is offering up to £1000 reward for information leading to their recovery.
They were destined for the Caledonian Railway tank engine No 419, which is at present undergoing a major overhaul at the Bo’ness yard before re-entering the stock mid-2013.
The theft will not affect the running of the society’s trains in the meantime but chairman John Evans said: “It will have a major impact on us, having to get them recast.”
He added: “They are of no use to anyone as they are. It is purely the value of the metal.”
The boxes, whose dimensions were 14 inches by six inches by 15 inches, would have needed at least two people to lift them, PC Lesley Hunter said on Wednesday.
They were stolen between the start of December and the end of January from a building in the yard beside Bo’ness Station.
PC Hunter said: “I am appealing for any information regarding this crime.
“This is a high value theft and every effort is being made to have the offenders caught.”
Anyone with information can contact her at Central Scotland Police on 01786 456000.