DMUs were manufactured in Japan, assembled in Nippon Sharyo's facility in Rochelle, Illinois, and towed by rail to Toronto, with the first trainset arriving on 15 August 2014. The trainsets seat between 115 and 173 people. On-board features include power outlets, Wi-Fi, luggage facilities, and washrooms. The UP Express DMUs are based on the design created for the Sonoma–Marin Area Rail Transit system in California. Powered by a diesel hydraulic drive with a six-speed automatic transmission and regenerative braking, the DMUs are believed to be the first trains in the world that comply with the United States Environmental Protection Agency Tier 4 emission standards, which will reduce emissions up to 90%. Braking energy is converted into electricity by the auxiliary power generator, and helps to provide onboard lighting and heating. They also comply with FRA Tier 1 crash energy management features. Modifications for UP Express use include enclosed overhead luggage bins that comply with Transport Canada rules and an enhanced enclosed luggage tower. Environmental impact The Tier 4 engines produce substantially lower emissions than most other diesel vehicles in Toronto. The Environmental Impact Assessment for the UP Express of 2009 was carried out assuming that trains would be Tier 3 standard rather than Tier 4, and showed that at peak frequency the air quality effect of the additional trains would not raise any pollution level above the provincial criterion levels. The 2010 Metrolinx electrification study, which did assume the use of Tier 4 emissions technologies for diesel propulsion options, found that the Georgetown/UP Express diesel service would contribute on the order of 0.2% to local air pollution, and that electrification would result in only a small improvement to local air quality. In an additional review of human health assessment in 2011, GO Transit examined the current plan for Tier 4 emission controls on both the UP Express trains and conversion of existing GO locomotives to Tier 4 and found that the human health risks of the diesel UP Express service are negligible, but that current background air quality (from other pollution sources in Toronto) is an issue. Fares and ridership Fares are based on age, origin and destination, and the method of payment (children ages 12 and under can ride UP Express for free year-round). Discounts are available for families, round trips, and airport staff. As with other GO Transit lines, integrated train tickets can be purchased through Via Rail