Square ventilation units are built every 30 m (98 ft 5 in) along the subway top to allow fresh air from the ground enter the construction site underground.

An 11 km (6.8 mi) long mostly elevated extension to Longquanyi began testing in April 2014 opened in October 2014.

[11] Line 3 runs in a northeast–southwest direction from Chengdu Medical College to Shuangliu West Station.

Line 4 runs in an east–west direction, stretching from Wansheng in Wenjiang to Xihe in the Longquanyi.

Testing began on the east of west extensions of Line 4 as part of Phase II expansion on 10 December 2016.

Despite the number, it was actually the sixth line to open, having started operation on 6 December 2017.

Like line 18 is uses a special variant of Type A trains with one less door per side and using 25 kV AC overhead power, as opposed to the "standard" 1500 V DC most newer metros in China use.

It parallels the southern section of Line 1 serving Tianfu New Area.

Like line 17, it uses a special variant of Type A trains with one less door per side and using 25 kV AC overhead power.

[14] The first phase of Chengdu Metro, consisting of Lines 1 and 2, were approved by the NDRC on 11 September 2005.

Riders can buy it through attendants in station's Service Centers or use ticket-vending machines.

If riders have not used the Single Ride Card, they may refund it at the same day at the same station.

[108] From its opening until 1 June 2017, Chengdu Metro used a fare system based on station counts.

[111] From 2 June 2017, Chengdu Metro starts new fare system based on distance.

[112] The Tianfutong Pass is a reloadable IC Card accepted by the Chengdu Metro.

[114][113] Additionally, passengers can pay for single rides directly using Debit IC cards offered by participating banks.

[117][118][119] Express lines meanwhile run on 25 kV AC to get to top speed quicker.

[120] Chengdu Metro Line 1, which opened to traffic in 2010, used a CBTC signaling system provided by Zhejiang Zhonghe Technology, a subsidiary of Zhejiang University,[121] in collaboration with Ansaldo STS.

[124] Chengdu Metro Line 3, which opened in 2016, was one of the first adoptions of a domestic CBTC signal system implementation by Beijing Traffic Control Technology.

[125] Beijing Traffic Control Technology's CBTC system is also used in Line 5.

[127] In response to congestion and high ridership, Lines 7, 8 and 10 are equipped with higher capacity 6-car aluminum alloy Type A trains.

[128] Lines 5, 6 and 9 are equipped with even higher capacity eight car aluminum alloy Type A trains.

[132] In 2008, Chengdu Metro in anticipation of the opening of Line 1, purchased and initial order of 17 six car trains sets from CRRC Qingdao Sifang.

[133] In April 2011, a further order was announced for trains from CRRC for Line 2, taking the total to 59 six car sets.

The tram system uses light rail trains, of each having 5 cars and 8 doors.

In early 2020, this line is included in the latest Chengdu Metro's official system map.

The city and the Ministry of Railways worked together in building high-speed intercity rail lines.