The Mountfield Tunnel is a single track tunnel in the south of England on the Turnbridge Wells to Hastings line in Kent, which was built 170 years ago. The track system inside the tunnel is a Pact system, which was built in the 1970s, that has to be renewed after 50 years of wear and tear in different phases. The portal at the north is called Robertsbridge portal, and the south portal is the Battle portal.
Phase 1 of the renewal works took place at the Robertsbridge portal, where a new track system was installed with a length of approximately 30 m. The slab track system is a reinforced concrete slab, with embedded sleeper type Cemex 1503. This track was designed by Schembera Consulting ZT, and installed in a 9 day line closure in October 2022.
The 2nd phase of the works took place at the Battle portal at a length of 230 m. The Pact slab was replaced with a slab track using Delkor Alt1 rail fastenings, which were embedded in reinforced concrete. The design of this track was reviewed by Schembera Consulting ZT as a CAT 3 checker.