Modernised Metro Trains In Sofia

On 4 February 2020 Metrovagomash sent eight Model 81-717.4/714.4 cars following their overhaul and modernisation to the Sofia metro. The contract was signed in December 2018 and includes an option for the modernisation of 40 more cars (= 10 units) of the same type in the coming years. The four-car trains, supplied with 750 V DC from the third rail and consisting of Model 81-717.4 end cars and 714.4 intermediate cars, are used on Lines 1 and 2.

The two modernised trains are formed of cars 1008 + 5008 + 5009 + 1009 and 1019 + 5019 + 5020 + 1020. The end cars have a length of 19.5 m over couplings, a weight of 32 t (± 3%) and total capacity of 254 passengers. The intermediate cars are 19.2 m long over couplings, they weigh 31 t (± 3%) and have a capacity of 266 passengers. The design of the 80 km/h modernised cars provides for the possibility of their mechanical and pneumatic coupling with existing Model 81-740/741 and 81-717/714 cars in the Sofia metro fleet. Overhaul and modernisation allowed to extend their service life by 15 years. The Model 81-717.4/714.4 cars are equipped with new inter-car couplings, the flammable interior materials have been replaced by those compliant with current safety standards. The cars are now fitted with smoke and temperature sensors.

Each car has a Bo’Bo’ axle arrangement, totaling 1,920 kW for each unit. The new asynchronous traction equipment, including new four-pole asynchronous traction motors, was produced by Hitachi’s Tokyo factory. The motors have a one-hour rating of 120 kW and were fitted also on the Budapest metro cars modernised by Metrovagonmash for Line M3 under the August 2015 contract involving 37 trains and completed in May 2018. Hitachi is already a supplier of electric components for Metrowagonmash’s metro trains, now in service in St. Peterburg and Budapest.

Metrovagonmash has been cooperating with the Sofia Metro since its opening in 1998. Currently, the entire subway fleet of the capital of Bulgaria consists of trains manufactured at Mytishchi and totals 168 cars. 

On 24 March 2020 TMH announced that Metrovagonmash and Sofia Metro signed a contract for option to modernise an additional batch of 40 Model 81-717.4/714.4 metro cars. The basic contract for modernisation of the first eight cars, with an option for 40 more, was signed in December 2018, and in February 2020 the eight modernised cars were sent to Sofia.

The new contract will be split into three phases: the first and the second phases involve modernisation of three four-car trains each (24 cars in total), and the third phase includes four four-car trains (16 cars in total). Each phase will take up to 12 months. Considering the load on the Sofia metro network caused by the trains withdrawn from service for modernisation, the manufacturer will strive to shorten the turnaround times.