[3] After World War II, electric multiple units (EMUs) in Poland were produced exclusively by Pafawag in Wrocław until 1997.

[7] In 2004, Newag, in collaboration with Energocontrol Kraków, designed the first EMU of their own construction, the 14WE, which began production the following year using parts from scrapped EN57 units.

[8] In 2007, Newag began designing a completely new unit, the 19WE,[2] in collaboration with the same company, then known as EC Engineering [pl].

In mid-May of that year, this unit was tested at the Railway Institute's experimental track in Węglewo near Żmigród and received an operating permit from the Office of Rail Transport [pl].

[15] Subsequent tenders for Szybka Kolej Miejska in Warsaw required low-floor units, disqualifying the 19WE/20WE.

[22] To meet this requirement, Newag conducted additional tests on one of the 19WE units after adding a second driver's seat.

As a result, the unit received an operating permit for 160 km/h, a speed for which it was originally designed, although not required by Szybka Kolej Miejska in Warsaw.

[23] Ultimately, on 17 October 2011, Koleje Dolnośląskie signed a contract with Newag for the delivery of 5 EMUs of type 31WE.

[15] Additionally, front vestibules are equipped with staff steps for crew boarding from the track level and passenger evacuation.

However, it is possible to couple two vehicles of the same type for multiple-unit operation (digital control by Medcom [pl]) using a retractable automatic coupler (Scharfenberg system by Voith).

[1][2][12] The car bodies meet the strength requirements of the PN-EN 12663:2002 standard (category P-II for multiple units).

[1][12] The trains are equipped with air conditioning (produced by Thermoking), forced-air heating, passenger information systems, four bicycle racks, a passenger counting system, ticket machines, video monitoring, and advertising monitors.

[29] (referred to motor shaft) (up to 6 km/h) The power system was developed in cooperation with Medcom, which designed the main electrical network and supplied the traction inverters (FT-300-3000[30] with IGBT technology),[2] static converters (PSM-60), high and low voltage distribution boards, and control panels.

[3] On 15 June 2009, the consortium of Newag and ING Group was selected in a tender for the 15-year leasing of 4 electric multiple units for the Szybka Kolej Miejska in Warsaw.