The firm has started redundancy consultation on more than 30 job cuts from management down to operatives.
Keltbray will also be downsizing the Welsh office in Treforest with all operations and commercial functions now being carried out through Crewe and Rugby.
Phillip Price, Group MD Infrastructure & Rail at Keltbray, said: “Keltbray’s rail electrification and rail civil engineering business is in good health with ongoing works and further successes expected through 2020.
“However, due to the lack of major rail piling projects in the pipeline for the next 18 months, we will be scaling down this area of the business and are considering making a small number of redundancies and redeploying people to other areas of the business.”
He added: “We are currently consulting with the employees affected to ensure they’re fully supported during this time.
“We have no plans to close any sites. This is about ensuring we’re in the right shape for when the CP6 work programmes come back to market.”