Arsonists started a major fire at a builder's yard in south Leeds, police have said.
Three buildings at Jewson builders' yard and Middleton heritage railway wagon in Lake Terrace in Hunslet were destroyed in the early hours of Sunday.
Richard Halderthay, of Jewson, said the fire caused "substantial damage" to the site off Moor Road.
West Yorkshire Police said the blaze "had been started deliberately with a number of separate seats of fire".
Mr Halderthay said: "The damage is very significant, it's a big store but one which we mostly deliver from rather than people coming to collect.
"The store was worst hit but the buildings where we keep vehicles wasn't so bad, so in that respect it's business as usual while we assess the long-term impact.
"We're making deliveries as normal at the moment."
All 16 staff have been redeployed to other local branches.
Ian Smith, vice president of Middleton Railway Trust, said a wagon storing all track maintenance equipment was destroyed.
The engine house's external cladding was also been damaged, and the external PA system and wiring was destroyed, causing around £30,000 worth of damage.
"It looks like something out of a disaster movie set, it's really awful," he said. "There's wood everywhere."
Sunday's railway gala was cancelled, but the yard will reopen on Saturday for the formal opening of the new running shed, to be opened by Leeds City Council leader, Judith Blake.