10 times less noise than the metro: the updated uBus U4-220-T2 has entered testing

After a range of modifications to the design, the U4-220-T2 uBus entered type testing. During the modernization, which took place in 2022–2023, engineers focused their main efforts on improving the consumer qualities and reliability of uBus systems.


A key improvement was the introduction of pneumatic elements in two stages into the suspension of the U4-220-T2 uBus. This significantly improved the smoothness of the ride and reduced the level of vibration and noise.

New compressors and variable speed fans were also installed. Completely new climate units and air ducts have been developed, through which cold or warm air is supplied to the passenger compartment.

UST Inc.’s Lead Design Engineer, Dmitry Vikhrenko said that all tests took place at speeds of up to 50 km/h and the established parameters were fully confirmed.

Ride as smooth as a business class car

Test results showed that the 48-seater U4-220-T2 uBus is superior to subway cars and trains in terms of smoothness.

The assessment was carried out on a scale from 1 to 5, the lower the number, the better. Thus, the smoothness of ride is up to 3.0 for train carriages, for metro cars - up to 3.25, and for the U4-220-T2 uBus - no more than 2.5.

Dmitry Vikhrienko noted that the smoothness of this uBus is at the level of a business class car.

Noise level is 10 times less

The external noise level of the U4-220-T2 uBus, according to test results, is 75.5 dBA, and the internal noise level is from 76 to 78 dBA, depending on the measurement point.

When compared with other urban rail transport, such as trams and metro, the external noise level of a metro train when moving in a tunnel ranges from 90 to 100 dBA, while the internal noise level reaches 95 dBA. The noise at stations during train acceleration and deceleration is 80 dBA.

The external noise of the tram when moving along tracks on crushed stone filling at a speed of 60 km/h is 86 dBA. If there is asphalt covering between the rails, then the noise reaches 91 dBA. The noise inside the tram is from 83 to 84 dBA at a speed of 45 km/h.

The resulting difference of 20 dBA means a reduction in sound pressure in uBus by 10 times compared to a metro or tram.

Testing of the U4-220-T2 uBus will end in November-December of this year. As noted by the Head of the UST Inc.’s field testing bureau, Alexander Loktevich, during the research a noticeable improvement in comfort parameters was recorded. He also emphasized that analytical work is being carried out and tests are continuing.

23 October 2023