TWO new carriages have been added to the assets of the Southern Downs Steam Railway Association.

The latest additions arrived at the Hamilton St workshop last week from Mt Alford, near Boonah.

The heritage carriages were rotting in a paddock opposite the Mt Alford school before being rescued by the Southern Downs group.

The 15-metre Davidson carts suit the style of locomotive on the tracks at the Warwick railway precinct.

Association president Peter Gregory said the carriages were close to 100 years old.

"We don't know too much about the history at this stage but they were probably made in the 1940s,” Mr Gregory said.

"Most of the carriages we have are around 80 to 90 years old.”

Currently operating with six carriages, Mr Gregory said the Mt Alford carriages would allow for more rotations.

"The more lines we get, the more we can rotate and keep up with the maintenance,” Mr Gregory said.

"When we find something from the same era, we have to hold on to it and can't let them rot completely.”

Preparing the out-of-order carriages for the tracks will be one of the team's biggest restoration jobs to date.

Mr Gregory estimates it could take up to 10 years.

"They're in a desperate state of repair, they're only a shell at the moment and will need a complete rebuild,” he said.

"The last restoration we did took four to five years and this looks like twice the job.”

Once up and running, Mr Gregory suspects the carriages would be able to take on 30 more passengers.

The volunteer-based group will persist in getting the carriages back on the track and hauling passengers, as they were designed to do.

A crane lifted the carriages onto a truck at Mt Alford last week for delivery to Warwick.