braking. EN57AKM In 2008, Koleje Mazowieckie decided to rebuild 10 trainsets into EN57AKM, during which LK450X6 AC motors developed by EMIT in Żychlin were installed. These engines were built in old housings, so that it was not necessary to change the final gears. The new engine has a power of 250 kW, and the entire unit 1 MW, which significantly improved the traction parameters of the vehicles – the acceleration of starting (up to 40 km/h) was increased to nearly 1 m/s2, and the maximum speed was raised to 120 km/h. Modernisations were carried out in the ZNTK "Mińsk Mazowiecki" plant (6 units in 2009–2010) and Newag Nowy Sącz (4 units in 2009), and the units modernised in this way were designated as EN57AKM. At the same time, SKM Trójmiasto commissioned the rebuild of one EN71 unit based on similar assumptions – it was carried out in 2009 by Newag, and on 14–16 October 2009 the unit was presented at the TRAKO 2009 International Railway Fair in Gdańsk. By July 2013, at a cost of PLN 351 million, another 21 EN57 units belonging to SKM Trójmiasto were to be rebuilt. This was to be carried out within 14 months by a consortium of Tabor Szynowy Opole (TS Opole) and Škoda Transportation, however, due to the bankruptcy of TS Opole, the rebuild of only one unit (EN57AKM-1718) was completed. In the re-tender for the rebuild of the remaining 20 units for SKM Trójmiasto, the most advantageous offer was submitted by the consortium of Pesa Bydgoszcz SA and ZNTK "Mińsk Mazowiecki" SA, which undertook said rebuild for approx. PLN 124 million. After the rebuild, these trains' top speed were increased to 120 km/h, with accommodations and ramps for disabled people. They are equipped with air conditioning (only in the driver cabs), toilets in a closed system, CCTVs and passenger information system (on monitors and audiovisual). EN57AKŁ From 2011–2012, Newag rebuilt four EN57 units into EN57AKŁ for Łódzka Kolej Aglomeracyjna on the basis of a contract awarded on 29 July 2011 worth PLN 31.4 million. Deliveries lasted from December 2011 to May 2012. The rebuilt trains are units 1226, 1452, 1044 and 1479. AC asynchronous motors were installed in the vehicles, which allowed to increase the maximum speed to 120 km/h. The units are also equipped with air conditioning in both the driver cabs and passenger interiors, two toilets in a closed system