In 1992, VR ordered the first 20 class Sr2 locomotives; later 20 more were ordered with 12 options. Finally only six of the 12 options were transformed into orders, forming a total fleet of 46 engines. The locomotives are used on both passenger trains and freight trains, and they are the primary locomotives of the fast InterCity trains in Finland. Until mid-2010s Sr2s were pulling IC trains the classic way, but after Edo-class cab control cars were introduced in 2013, Sr2 units have been used in pull-push mode with IC double deck stock. Until introduction of new Sr3 locomotives, Sr2 has been the only electric locomotive equipped for push-pull among Finnish rolling stock.
Technical information
When introduced, the Sr2 was the fastest and most powerful locomotive of the VR. It was designed with a top speed of and early units had that speed marked on them. During test runs, it has achieved a speed of. However, VR later limited the top speed to, since test runs require 10% faster speed than the targeted commercial speed. The locomotive has GTO-thyristor inverters driving three-phase asynchronous AC motors. The maximum power of each air-cooled motor is at 2,600 V. Combined, they are capable of a power output of . The motors are small and fit entirely within the bogies. The bogies weigh only 15.8 tonnes and are equipped with radially steered axles. This reduces rail wear significantly. A redesigned bogie construction was refitted by the manufacturer in the mid-2000s after the locomotives were found to oscillate sideways when running at speeds of over. The whole construction of the locomotive is modular and all functions are controlled by several microprocessors via the locomotive bus. The system is redundant, so that a failure in one processor does not harm the overall system. The data lines are fiber optic cables. Sr2 units are fitted with Unilink couplers, which combine a SA3 and a traditional chain coupler.
Design and livery
As with all the Lok 2000 locomotives, the external design is by Pininfarina. The series were painted red and white, showcasing VR's InterCity colours, with a large V on the bodyside to symbolise VR's high-speed traffic. Starting from number 3222 the V was replaced with VR's logo. Beginning from 2010 and starting from engine number 3221, all units were repainted with VR's current colour scheme.
