That's equivalent to less than 2.4% a year, which suggests you were looking at general inflation. Construction industry inflation is always much higher, but I don't know a figure.
Construction inflation indices are here:
Construction output price indices - Office for National Statistics
Construction Output Price Indices (OPIs) from January 2014 to December 2023, UK. Summary.www.ons.gov.uk
I was not aware generally construction inflation was significantly higher than general inflation. While house prices have increased significantly more there is a big difference between the estate agent price and the insurance rebuilding price.
There’s also been “standards inflation” for new construction stations. Some of the 1990s new station quality was pretty hopeless.
Indeed a valid point.
What I would like to see is a cost comparison for exactly the same work between 1991, when it would have been carried out or at least managed by British Rail, and 2021, with fragementation between TOC's, Network Rail and maybe others. In light of the first point further the difference between the increase for general construction e.g. houses, offices and railway stations and infrastructure.