Engineers at the Severn Valley Railway are working in a race against time to overhaul one of the heritage line's most hard working steam engines.
They're carrying out a £35,000 overhaul of the Flying Pig, which has been in service at the railway for more than 40 years.
It was one of the first engines to run when the attraction opened to the public in 1970.
It's affectionally known as the Flying Pig because when the LMS Ivatt Class 4's were built between 1947 and 1952, they were considered to be the ugliest locomotives of their time.
More than 160 were built, but engine 43106 is now the only one left.
For this reason, the restoration team at the Severn Valley Railway say it's much loved by passengers and enthusiasts.
This overhaul is to replace the engine's backplate where the driver and fireman stand.
Alongside this the boiler has also been removed to carry out some other additional repairs.
– Duncan Ballard, Boiler Manager, Severn Valley Railway
"It's part of our winter maintenance locomotive 43106 has come in for an intermediate repair. We've got some mechanical work to do on her and whilst we're doing that we thought it'd be useful to take the boiler out. There's issues and faults with this, so I'd say this is an MOT with a few jobs being done on it."
In comparison to other repair jobs this one is relatively small. The average cost for a small engine rebuild is around £50,000, but most jobs carried out at the works in Bridgnorth are between £250-£500k.
Duncan says they're no longer easy and quick fixes, as the machines are nearing 70-80 years old.
One of the engine fitters working on the Flying Pig is Will Marsh. He started work at the Severn Valley Railway as an apprentice 6 years ago.
– Will Marsh, Fitter machinist
"The apprenticeship I served is very different to modern apprenticeships as far things go because it is heritage skills, there's no computers here for manufacture - it's all done as it was from in the 1900s right through to the 1960s. I'm involved operationally. I'm a fireman, I'm a signalman I get involved voluntary as well at weekends - it's probably mad!"
Funding work like this sometimes comes from private donors, but most cash comes from ticket sales.
Duncan Ballard says the only way the railway and restorations can keep going is if people keep visiting the attraction.
The line runs 16 miles between Kidderminster in Worcestershire and onto Bridgnorth in Shropshire.
Earlier this year the heritage line put £3million pounds of shares up for sale to the general public, and after 6 weeks £750,000 of them were sold.
The team working on the Flying Pig have got a tight timetable to get the engine back on track.
At the moment the locomotive is in bits, but the aim is to get her running again in time for the summer season.