Rail fares on most commuter routes are set to fall in January for the first time since privatisation in the 1990s.

The average cost of a peak time train ticket should drop 0.4 per cent in the New Year after inflation measured by the retail price index remained in negative territory last month, at -1.4 per cent. The July RPI is used to set prices for the following year, with increases limited to no more than 1 per cent above inflation.