The cars will be formed into 16 four-car and eight six-car trains. They will be built partly in Switzerland and partly in a new factory in Minsk, Belarus, which Stadler will complete this autumn. Delivery is expected to start in 2015 and be completed by the end of 2016.

The 1520mm-gauge trains will be based on Stadler's Kiss design, but will be larger than the standard-gauge trains Stadler builds for customers in western Europe. The cars will be 3400mm wide compared with 2800mm for the European version and 5240mm high compared with 4500mm. The trains will be designed to cope with temperatures ranging from -40oC to +40oC.

Traffic on Aeroexpress services has been growing strongly and the three Moscow airport routes carried 14.9 million passengers last year. This is expected to grow to 21.1 million by 2015, and Aeroexpress says the new double-deck emus, which will replace single-deck trains, will increase capacity by 30-40%.

Last week Stadler secured a contract for 28 emus, including 13 Kiss trains, from leasing company Alpha Trains for use by German operator Westfalenbahn.