[11][12] Selection criteria included not only price but also the technical merits of the proposed rolling stock, the company's references, and the participation of domestic manufacturers in the delivery.

[11] The contract guaranteed the delivery of Metropolis 98B trains adapted to Polish requirements and the Soviet loading gauge used in the Warsaw Metro.

[10] The trains produced at the Alstom Konstal plant covered the 260 km (162 mi) route from Chorzów to Warsaw on their wheels, towed by an electric locomotive.

After transporting the trains to Warsaw, the main tests were conducted on the metro line to confirm the technical parameters of the cars.

Over a month, the trains underwent detailed gauge measurements, technical inspections by staff, manufacturer acceptance procedures, certification processes, and trial runs on the test track.

The primary components of the front coupler include a head permanently connected to the pin, a draw-and-buffer device, and centering spring cylinders.

[34] In late October 2013, Warsaw Metro announced a tender for the major overhaul of Metropolis trainsets, which would include a change in the vehicle livery – the blue stripe was to be replaced with yellow film, and the front around the windows was to be repainted red.

[41] In mid-2013, QR codes were added to the roofs of Warsaw Metro vehicles, including Alstom trainsets, for train inventory purposes at STP Kabaty.

The left side of the cockpit has a COMET 1 console – a diagnostic system interface providing real-time information on train parameters, detected faults, and malfunctions.

[28] Air springs are installed on recessed parts of the side frame beams, forming the second stage suspension, with the body suspended on them.

Due to space constraints on the driven axles, single discs are mounted, with actuators and brake shoes suspended from tubular front beams of the frame.

[26] Under each of the middle M cars, there is a power inverter box housing two ONIX 800 traction inverters, drive control electronics, and the basic components of the main inverter circuit such as an input filter with choke, over-voltage protection system, keys consisting of three IGBT modules connected in parallel, braking chopper, quick switch control module, sensors and protective relays, input and capacitor charging contactors, workshop switch, and a cooling fan with its control.

Two are positioned so that their horizontal axes are on the upper side of the central part of the bogie, bearing vertical, transverse, and longitudinal loads.

It directs airflow to the heat exchange channels on the outer perimeter of the magnetic circuit, with its externally toothed turbine serving as a speed sensor disk.

At the non-drive end, the cover functions as an air flow diffuser from the fan and supports the bearing, allowing the installation of a speed sensor.

The drive end cover is ribbed, providing greater mechanical stiffness and improved heat exchange with the external cooling airflow.

The drive-end journal is designed for mounting a gear coupling connected to the gearbox, while the non-drive end features a speed sensor disk.

The non-drive end disc acts as an air flow diffuser from the fan, supports the bearing, and allows the installation of a speed sensor.

The drive end cover is ribbed for increased mechanical stiffness and improved heat exchange with the external cooling airflow.

[26] Under the body of each cab car Tc, there is a maintenance-free nickel-cadmium battery with a capacity of 90 Ah, housed in a ventilated box mounted to the chassis.

[26] The source of compressed air in the train are two SL 20-5-66 rotary-screw compressors, each mounted under the body of a cab car Tc and driven by an 11 kW three-phase AC motor.

[26] In emergency situations or during maintenance and repair, the system can be supplied with compressed air from an external source through couplings in the front-end connectors.

The car bodies were tested in a specialized laboratory in Belgium, and the materials used in their construction comply with Polish standards in terms of flammability, toxicity, and smoke emission.

[28] Metropolis cars, although equipped with onboard diagnostic devices, are maintained according to a rigid and formalized cycle that treats the vehicle as a whole.

[47] The diagnostic system installed in Alstom trains affects the scope of repair work when an abnormality in the operation of any component is detected.

[54] In December, train number 24 was the first to return to Warsaw, and at the beginning of February 2017, it was undergoing final tests before being put back into operation.

[6][57] Studies showed that excessive vibrations occurred during the transit of Metropolis train sets due to a phenomenon known as wheel ovalization.

It was determined that the monoblock wheels used by Alstom wore unevenly around their circumference, causing the vibrations felt by Warsaw residents due to their irregular movement along the tracks.

Since identifying these defects, the problem was temporarily resolved by re-machining the deformed wheels on a special track lathe installed at STP Kabaty.

The tests aimed to check the control systems and the behavior of Alstom trains on this section, so they could be operated on Line M2 in the future.