"If you'd invested 15 or 20 years ago into engine name plates you would have seen a phenomenal return," says David Nathan, a cataloguer for Vectis Auctions. "You could have bought a castle-class locomotive name such as Abergavenny Castle when it was sold as scrap by in the mid-Sixties for around £10 - now you are talking £25,000 to £35,000."
Tony Hoskins, who runs one of the UK's leading railway memorabilia auctions, GWRA, agrees. "Fifteen years ago the top price for nameplates was about £15,000 but the record now stands at about £60,000."
Even the cast bronze numbers that were on the locomotives have been fetching a lot of money.
More recently, interest has spread to "totems", enamelled signs once found in stations. The record price of £8,150, held by GWRA, is for the Evercreech Junction station sign.
"The things to buy are those which are unfashionable because the chances are they will increase more," advises Kegan Harrison at Bonhams. "One of the cheaper areas is silver and crockery items - these don't make a lot of money despite the fact that not much has survived in good condition.
"Tickets have become collectable - 99.9 per cent are worth less than 50 pence but we hold the world record for the most expensive - which was £2,700."
David Nathan at Vectis also thinks there are opportunities for railway collectors with less money. "There is a lot of stuff that is very cheap now and would go up in price. Interesting things include signal box indicators and station clocks," he says.
"Once you could hardly get rid of these clocks, but now pre-nationalisation examples with the GWR or Southern Railway mark are worth £1,000 or more."
Chris Dickerson, at Sheffield Railwayana Auctions, adds: "People are now turning to paperwork to improve their collections. Enthusiasts are also interested in things such as carriage prints. Books and photographs are growing."
Posters have also been very popular. Prices are high because they attract fine-art enthusiasts - train companies commissioned some of the best artists of the day to produce them.
The crème de la crème is pre-1920s material from the heyday of steam. But while there is a nostalgia in this market, fewer and fewer people remember steam trains and Nathan believes interest will wane.
"The next surge will be in diesels or electric locos as many younger people have only seen those," he says.
Dickerson adds: "There's quite a big interest now in diesel name plates and numbers which are increasing in value and in some cases are up there with steam."
However if you buy top quality steam-age items it's unlikely this market will ever disappear. With youngsters brought up on Thomas the Tank Engine and visits to the local steam railway, the age where the train was king is unlikely to reach the end of the line for collectors.Reuse content