The South Eastern Railway (SER) first reached Tonbridge (then known as Tunbridge) in May 1842.includeonly> The site of the original station was on the east side of the road bridge over the railway, opposite its current location to the west of the bridge.includeonly> The building of the station obliterated the last remains of Tonbridge Priory. At the time, the line ran to London Bridge via Croydon and Redhill using the Brighton Main Line. It served as a temporary terminus until December 1842, when the line reached Ashford. A couple of years later the through line to Dover opened. A small engine shed was built; the date of opening is uncertain but it is presumed to date from the opening of the line. On 20 September 1845, a branch to Tunbridge Wells opened and the station was renamed Tunbridg