[5][10] In 1993, it was decided that the last 80 carriages of the order would be built to a modified design to operate peak-hour services to Wyong, Port Kembla and Dapto.

In early 2000, set G7 was also subject to high-speed testing (to the XPT speed limits) up to 150 km/h (between Blacktown & St Marys) & 140km/h (between Hornsby & Newcastle) [17].In 2010, a refresh of the Tangaras commenced with the interiors repainted, and new seat moquette and handrails fitted.

[18][19] In July 2013, Sydney Trains trialled rearranging the seating on the upper and lower decks of two carriages.

[25] The door kicking incidents often led to unnecessary delays as the guard had to lock off the affected carriage.

The upgrade still went ahead however, with vestibules given modifications including marked priority seating and Automatic Train Protection (ATP).

The program includes overhauling air conditioning units, Static Inverter upgrades, and modifications to the Driver's desk/cab.

Trialed in 2015, these sensors are able to detect vapors from strong permanent markers and spray paint; triggering an in-built camera feed which is relayed to Sydney Trains staff as well as the Police Transport Command.

[29] On 10 February 1994, set T99 travelling from Richmond towards Blacktown collided with a van at the level crossing at Vineyard.

[30] Set G7 derailed on 31 January 2003 near Waterfall, killing seven people aboard including the train driver.

The driver suffered a sudden heart attack and lost control of the train while the deadman's brake failed to activate as intended.

[31] During evening peak on 15 January 2014, motor car N5222 on set T10 was pierced by a guard rail near Edgecliff railway station while on a service to Cronulla.

As the train entered the Eastern Suburbs Line, a strong burning smell was reported at several stations.

It was later revealed that an incorrectly repaired axle on N5222 led to the force of the 440-tonne train picking up the piece of guard rail.

It wasn't successful and after spending large periods out of service, being withdrawn in December 2002 and stored at Newport Workshops.