In 2013, a diagnostic computer at Guangzhou Metro broke down. It was worth tens of thousands of yuan. The quote to replace it: 1 million yuan (S$192,300).
The machine contained software for checking the on-board signalling systems of 21 trains. Back then, suppliers often sold the device and its software only as a bundle.
Guangzhou Metro did not pay. Instead, that episode – a “painful experience” – pushed Cai Changjun, then the general manager of its operations division, to develop creative solutions.
One of them, Suiteng OS, is being adapted and tested in Singapore at the SMRT-Guangzhou Metro Rail Innovation Laboratory, launched at Bishan Depot on June 3, 2026.
Suiteng OS was first deployed at Guangzhou Metro in September 2019. It is a rail operating system that can be updated the same way as a smartphone’s operating system.
Today, Cai, 61, is lending his expertise in Singapore. He advises SMRT on a range of technical matters, including making the MRT network easier to upgrade and maintain, and improving rail operations and commuter experiences.
He sits on the public transport operator’s Technical Advisory Panel (TAP), and is one of five members of the Land Transport Authority’s Independent Advisory Panel.
Components of railway systems used to be built like sealed products, explains Cai, who retired last year as deputy general manager of Guangzhou Metro. He joined in 1995, before its first line opened in June 1997.
The metro network is now one of the largest in the world, with 19 lines spanning 780km of track and nearly 400 stations.
“When the hardware breaks, (operators cannot simply) replace the hardware and reinstall the software,” Cai explains in Mandarin.
“It’s like buying an old feature phone (that’s not a smartphone),” he adds. “Whatever functions it has when you first buy it, is what you have.”
Now, hardware and software can be decoupled, and software development is modular. This makes it simpler for public transport operators to upgrade their systems.
Cai’s career spanned some of Guangzhou Metro’s most complex operational and technological upgrades. He holds 36 invention patents, including the building blocks of Suiteng OS – such as one that lets the system automatically recognise new equipment once it is installed, and a system that can track train speed and location.
In an interview on the sidelines of the 13th TAP held from Oct 14 to 16 at SMRT’s headquarters, Cai reflects on learning on the job, what he thinks about Singapore’s MRT network, and what a commuter-centric public transport experience looks like.
Cai (middle) speaking with SMRT leaders on the sidelines of SMRT’s Technical Advisory Panel on Oct 16.
PHOTO: CAROLINE CHIA
Lessons on the line
How does it feel to see Suiteng OS being tested in Singapore?
A: I feel very gratified and proud to see it being trialled here.
Metros in different cities share some things in common, but passengers’ travel patterns, cultures and service needs differ. SMRT will have to (build applications on Suiteng OS that) suit its own operations and service needs in Singapore.
Suiteng OS was not created for one specific scenario. It was built on a more fundamental, service-oriented philosophy, so it’s adaptable and not a fixed product.
Because the train network is like a living organism. It keeps growing; it doesn’t stay at just one line. What passengers want changes too. But once the system is fixed, it can’t meet these changing requirements.
In the early 2000s, you came to Singapore to learn about rail operations from SMRT. What stood out for you?
A: I was here to learn about the Bukit Panjang LRT, as Guangzhou Metro was looking into building similar automated train systems at that point.
Two things left a deep impression on me.
First, whenever the train passed in front of a residential block, the windows automatically turned opaque. What this showed me is that the city’s train systems were built on a people-centred design philosophy.
Second, there was a self-service counter between the paid and unpaid areas, so the stations could run without staff. That was considered very advanced at the time.
Cai (front) at Guangzhou Metro’s Xilang Depot in November 2024, inspecting the overhaul of its trains.
PHOTO: COURTESY OF CAI CHANGJUN
Why is it important for train operators to learn from each other?
A: When China first began building urban rail, we learnt from the most advanced train operators at that time: Germany, France, Hong Kong and Singapore.
While we have made progress, it doesn’t mean we can start being complacent. If others have been through challenges that you might face in future, you can save a great deal of work by learning about it now.
As an international city, Singapore has a quality captured by the Chinese idiom: “a sea that takes in a hundred rivers”. The city is willing to learn from everyone else, and I believe that is what gives it an advantage.
What does public transport mean to you?
A: The basic function of public transport is getting people to their destinations.
But in a big city, a person can spend an hour a day or more on the metro. Part of their life gets woven into that journey, so the service can’t simply be about getting them from point A to point B; it also has to meet other needs, such as convenience, food and even entertainment.
Rapid transit can also expand a city’s space by shortening distances in space and time. If transport isn’t convenient or efficient, everyone will end up living close to where they work, which can strain the city’s living environment.
Public transport, especially rapid transit, opens up more living space. That’s good for the city’s development, and good for improving where residents live.
Cai (first on the right) at the site of an electrical system upgrade for Guangzhou Metro Line 1’s oldest trains in April 2024.
PHOTO: COURTESY OF CAI CHANGJUN
Looking back, what are you proudest of?
A: Being part of such a magnificent wave of rail construction, which is now serving Guangzhou’s nearly 20 million residents.
Every year, Guangzhou Metro carries 3.3 billion passenger trips. Making residents feel the metro is reliable, and making it part of their daily lives, is something worth being proud of.
Once, a reporter asked me: if you could do it all again, how would you have built the metro differently? I replied that I have already given it my best shot. Not many people get to be part of such a large project – Guangzhou Metro built 19 lines in span of 30 years – over the course of their career.
My colleagues and I kickstarted it; those who come after will continue to make it even better.
Experts behind the tracks
Guangzhou Metro veteran Cai Changjun, 61, is one of nine experts invited to be part of SMRT’s 13th annual Technical Advisory Panel (TAP) held from Oct 14 to 16, 2026.
Experts who attended this year’s TAP include:
Lee Kang-kuen, professor of Practice (Transportation) at Hong Kong Polytechnic University, who has over 50 years of experience in trains and railway design, maintenance, and upgrading projects; and
Tsuyoshi Tabuchi, president of Osaka-headquartered rail construction and engineering firm JR West Railtec, and an expert in track infrastructure.
Set up in 2013, the annual TAP brings together international and local experts to exchange insights on rail engineering capabilities, people, processes and technology.
The aim: To improve SMRT’s operational performance and strengthen engineering expertise. SMRT notes that past TAP sessions have led to improvements in rail assets maintenance programmes and more adoption of condition monitoring on train and signalling systems.
At the session on Oct 16, Cai shared automation solutions that he implemented at Guangzhou Metro before retiring last year. These include:
360-degree multi-camera systems that scan every train entering or leaving the depot for defects;
Robots that inspect the underside of trains; and
Inspection systems mounted on rail vehicles that survey tunnel walls at up to 80 km/h, a job once done by workers on foot in the early-morning hours.
Topics presented by other experts at the same session include robotics in rail construction and maintenance, artificial intelligence and cybersecurity for rail systems.
Cai is also one of five members of the Land Transport Authority’s Independent Advisory Panel (IAP).
“Being able to come to Singapore and serve on both the TAP and the IAP is truly an honour,” he says. “(It is) a recognition of my career.”
Because Guangzhou Metro both owns its rail assets and runs its network, Cai has worked on both sides of the table. This lets him see issues from the perspectives of both the asset owner and the operator.
Ultimately, he adds, “the goals are the same: to provide the city with public transport people can trust.”
This article was produced in partnership with SMRT.