The line is owned and operated by BC Rapid Transit Company, a subsidiary of TransLink, and links the cities of Vancouver, Burnaby, New Westminster and Surrey.

Just east of Columbia is a junction, one branch of which crosses the Fraser River, via the SkyBridge, and is elevated for the rest of its run through Surrey, with King George as its terminus station.

What is now known as SkyTrain began as a demonstration project to showcase the newly developed linear induction propulsion technology to Vancouver and other prospective cities throughout the world.

The walkway between the two tracks is of a different but also inferior design from the Expo Line, and it is showing signs of rust that come with the older age of the guideway.

The ICTS guideway was retrofitted during the construction of the Millennium Line to accommodate the heavier weight Mark II cars.

With the exception of the original ICTS guideway, no other part of the Expo Line required retrofitting for strength in order to accommodate the Mark II cars.

After the 1983 preview closed, the single pair of demonstration cars were sent back to Ontario, which have since served as test trains for the UTDC.

Construction began in 1987, with Columbia station opening on February 14, 1989, adding 600 metres (2,000 ft) of guideway in the City of New Westminster.

[citation needed] The second segment opened on March 16, 1990, and included Scott Road station in Surrey, crossing the Fraser River via the purpose-built, cable-stayed "SkyBridge", adding 2.5 kilometres (1.6 mi) to the line.

[6] Construction of a 4-kilometre (2.5 mi) second extension, or Phase III, began in late 1991 and opened on March 28, 1994, adding three stations in Surrey's City Centre district in Whalley.

[7] Private partnerships with surrounding businesses in the community led to the then-new stations having a different appearance from the rest of the Expo Line.

On October 22, 2016, this branch began service from Columbia to Sapperton, Braid, Lougheed Town Centre, and Production Way–University stations, while the Millennium Line began running between VCC–Clark and Lougheed Town Centre (and later, Lafarge Lake–Douglas) stations, effectively ending nearly 15 years of Millennium Line service between Waterfront and Braid.

The main Expo Line service between Waterfront and King George stations remained in place, operating at the same frequency levels.

Before the purchase of some Mark II vehicles in 2009, the Expo line was operating at capacity while carrying 12,000 passengers per hour per direction (pphpd).

[10]: 1, 16 Several options have been considered over the system's history to increase capacity on the Expo Line, including: In late 2020, TransLink ordered 41 Alstom Mark V trainsets in five-car configurations.

[14] The order will provide for both an increase in the number of trainsets and ultimately a total replacement of the mid-1980s to early 1990s Mark I rolling stock.

[26] The existing funding would extend the line 7 kilometres (4.3 mi) to Fleetwood in Surrey and add 4 new stations, terminating at 166th Street.

[27] The council also voted to proceed with preparing a detailed business case for the full Surrey–Langley SkyTrain extension, which was expected to be completed by early 2020.

[26] On October 8, 2020, during the 2020 provincial election campaign, the BC NDP pledged to work with senior levels of government to obtain the $1.5 billion needed to complete the full extension to Langley.

[28] On July 9, 2021, Prime Minister Justin Trudeau announced that the federal government would provide up to $1.3 billion to build the SkyTrain extension to Langley in a single phase.