another 10 years. Upgrades included overhauls to the mechanical and electrical systems, the addition of new LED interior and exterior destination signs, additional speakers to improve sound volume, and retrofits for CBTC operation for the Metro Line. Refurbishment was done by Bombardier Transportation in Buffalo, New York. Retirement In 2010, the San Diego Metropolitan Transit System sold 35 cars to Mendoza, Argentina, followed by the bulk of its U2 fleet retiring in 2013, when the Orange Line received low-floor cars. The remainder were used on its initial operating segment until January 2015. In 2016, two cars were shipped to Texas for use at a dog training facility, The majority of the U2's had left the property by 2018, having been either scrapped or donated to museums, with car 1001 being retained. After 48 years of service, the last Frankfurt examples were retired in April 2016. The Frankfurt cars have been replaced by Bombardier Flexity Swifts. There are three cars left for museum purposes Calgary Transit has begun a similar retirement system as they have begun to introduce the Siemens S200 as both a replacement and expansion of the fleet. The city has begun to explore additional disposition options. The U2s in Calgary had been retired in 2016 but there are still 40 in service out of 83 DCs and 2 ACs. Edmonton Transit Service has announced that its 37 U2s will be replaced by 2030, as they intend to procure new LRV's between 2023-2024. They have also stated that they are looking into preserving at least one vehicle for their historical fleet. Technical details The U2's dimensions are by by . In the US and Canada, usually up to five U2 cars are coupled to run as a train. Calgary Transit regularly couples up six U2 cars to shuttle them from Anderson Garage to Haysboro storage. These unique shuttle trains can be commonly seen after the evening rush hour. Each articulated car has a total passenger capacity of 264 passengers. It may be equipped with two DC motors for a total power output of and a maximum speed of , or with four AC motors for an output of and speed of . As the length of a tram or light-rail train running on shared track is restricted to a maximum of in Germany, up to four U2 cars may be used in a single consist on such track. Frankfurt