Motor points and colour light signals were installed at Khandallah in January 1938. Tablet remained in operation until the third of July 1938 when it was cancelled. The full Wellington - Johnsonville automatic signalling came into operation on the fourth of July 1938.

The Up Starter, with the Departure on the single line, was provided to allow up trains to divide, with one half returning to Wellington.

A-lights on the Up & Down home signals avoid detention of a train at the respective home signals in the event of a preceeding train failing or a track fault occuring within station limits.

Further research is needed into Khandallah as a tablet station. In 1908 Tablet machines were installed at Thorndon, Ngaio and Johnsonvlle. It is possible that Khandallah may have received machines later.

Converted to an unstaffed crossing station - signal box removed.

Up Starter converted to single unit and reclassified as a departure - the facility for dividing trains was thus removed. Signal 25 Shunt From Main removed. Backshunts and mechanical shunt signals removed.

"Distant" signals renumbered from "R3" to distance based format. Did their function change?

Signals and points renumbered.

CTC was installed and the points and signals renumbered, using the conventions for remotely controlled loops.

Down Departure from Up Main and Up Departure from Down Main three-lens signals were installed. The A-Lights were removed.

To avoid expensive changes to the interlocking the low-speed lights were set up to prove the track unoccupied, which is contrary to normal practice.

In 1977 distances had been metricated.