Railway gft Polska Sp. z o. o. delivered materials for the track superstructure as part of the investment: "Renovation of the tram track in Aleja Wielkopolska in Poznań together with the reconstruction of the Klin platforms", the Investor of which was Miejskie Przedsiębiorstwo Komunikacyjne in Poznań and the General Contractor was NDI Energy. The uniqueness of the implementation consisted in the use of Y-type steel sleepers in the ballasted tram track. Due to the need to protect the root system of the chestnut trees that grow along the tram line, the Contracting Authority decided to use Y-type sleepers. Y-type steel sleepers allow for a reduction in the structural height of the track compared to the ballasted track using standard pre-stressed concrete sleepers. The construction of the track with Y-type steel sleepers allowed for less interference with the track substructure and thus the protection of old trees.
