Union Pearson Express 1001-1012
Union Pearson Express 1001-1012 are diesel multiple units (DMU) manufactured by Nippon Sharyo in 2014. The twelve DMUs are operated in sets of two or in sets of three with a "C" car which does not have a sloped end.
Refurbished Budd RDC cars were initially proposed to be used on the airport rail link. Electric trains were not planned to be used until at least 2024. The added rail traffic from the Air Rail Link and expanded Georgetown Line service would mean more exposure to diesel exhaust by residents, and thus residents and health official began voicing their concerns. Vocal opposition to diesel trains began with rallies and the formation of the Clean Train Coalition. In July 2009, Metrolinx undertook a study on the electrification of the GO Transit rail network. It was completed in January 2011 and the Metrolinx board voted to implement electric trains on the ARL and the Georgetown and Lakeshore GO lines. Implementation, however, would not take place until 2017 or 2018 at the very earliest Diesel trains would have to run in the interim.
On February 18, 2011, the Metrolinx board approved the purchase of 12 diesel multiple units (DMUs) from Nippon Sharyo USA. The initial contract, which includes capital spare parts, special maintenance tools and contingencies for Metrolinx design changes, is valued at aapproximately $55 million. An option for an additional six DMUs, if exercised, would put the value of contract at $75 million. Metrolinx was able to get a favourable price for the DMUs by joining a competitively tendered process used by the Sonoma Marin Area Rail Transit (SMART) in California. The DMUs will be Tier 4-compliant and will be able to be converted to electric propulsion.  The option for six additional DMUs was taken in October 2011 and will allow for six three-car trains. 
The DMUs begin construction at Nippon Sharyo's Toyokawa facility in Japan. Final assembly takes place at the expanded Rochelle facility in the United States. The first two cars were shipped to the United States in the summer of 2014. Metrolinx had initially forecast the prototype to arrive a year earlier. The remaining cars are expected to arrive in Toronto by the end of the year.
- (16 June 2009). Electrify west end GO line, say health officials and residents. Canadian Broadcasting Corporation. Retrieved on 2011-01-28
- Kalinowski, Tess (26 January 2011). Queen' Park On Board with Electric Trains. Toronto Star. Retrieved on 2011-01-28
- Metrolinx Board of Directors approves purchase of vehicles for Air Rail Link (Press release). 18 February 2011. Canadian Newswire. Retreived on 2011-02-19
- . Sumitomo Corporation of America. Retrieved on 2012-08-15
- Air Rail Link Vehicle. Metrolinx. Retrieved on 2011-02-19