The LRT Ampang Line is named after its eastern terminus, Ampang station, while the LRT Sri Petaling Line is named after its former southern terminus, Sri Petaling station.

The LRT Ampang and Sri Petaling Lines form part of the Klang Valley Integrated Transit System, numbered 3 and 4, and are coloured orange and maroon on official rail maps respectively.

[citation needed] STAR-LRT was first conceived in the 1981 Transport Master Plan, when the Malaysian government proposed a network of LRT lines connecting Kuala Lumpur city centre with the surrounding areas.

Phase two (15 km (9.3 mi)) consists of 11 stations (Chan Sow Lin – Sri Petaling, and Sultan Ismail – Sentul Timur).

Thales was awarded a contract on 3 September 2012 to upgrade the signalling system on the original line, and the work was completed in July 2016.

[13][14] Stations on both the lines have similar architectural designs and are a mixture of surface and elevated stops.

The LRT Ampang and Sri Petaling Lines system network fleet consists of the following models: The former fleet consisted of 90 Adtranz standard-gauge light rail vehicle (LRV) manufactured by Walkers Limited of Australia.

These trains were electric multiple units (EMU), which draw power from the underside of a third rail alongside the track.

This formation were used in service until the centre trailer cars were added, becoming the six-car trainset, which consisted of three sets of two EMUs (2+2+2) and occupied the maximum platform length of the stations.

There were no individual seats, only longitudinal bench seating on either side of the train, surfaced in metal, while spaces near the connecting ends of the cars were provided for passengers who use wheelchairs and other assistive devices, with a large amount of floorspace for standing passengers.

Each of the new trains is six cars long[15][16] and provided by CSR Zhuzhou of China, similar to on the design for İzmir Metro and Buenos Aires Underground 200 Series.

Other elements such as interactive destination display inside the train, non-slipping seats, LCD infotainment, walk-through gangways, and more wheelchair space were included.

[18][19] The first trains were put into service on the Sri Petaling-Kinrara BK5 stretch in October 2015, and then until Putra Heights and Sentul Timur in July 2016, and finally the Ampang branch line in December 2016.

Individual cars are assigned a four-digit serial number by the rail operator Rapid KL.

A complete six-car trainset consists of four trailer (T) and two driving motor (Mc) cars permanently coupled together.

On 27 October 2006; 18 years ago (2006-10-27) at 7:11am, a six-coach Adtranz LRT train which came in from Ampang overshot the end of the elevated tracks at the end of the stabling tracks at Sentul Timur station, resulting in the front half of the set 1113 dangling in the air about 25 m above the ground.

[27] On 24 September 2008; 16 years ago (2008-09-24) at 6:30pm, two LRT trains collided about 200m from Bukit Jalil station.