Padua SIR2: Precision and Innovation for Lot 2

GCF's contribution to the new sustainable tramway line

A concrete platform built with millimetric precision, a monorail guidance system, electric traction installations and power substations designed as a single integrated system. This is the technological core of Lot 2 of the new SIR2 tramway line in Padua, where GCF SpA carried out the specialist works that will enable the operation of the future infrastructure. A PNRR-funded project that, by the end of July, had achieved all the targets set by the European Union to qualify for funding.

From Padua railway station to Busa di Vigonza, passing through the courthouse, the university, the exhibition centre, business districts and the future hospital complex, Lot 2 of the new SIR2 tramway line is much more than a new tram route: it is an integrated system in which civil works, trackwork and technological systems operate as a single organism.

The specialist works were carried out by GCF - Generale Costruzioni Ferroviarie which, within a Temporary Consortium of Companies together with Vittadello SpA (lead contractor) and Sielte Trasporti Srl, contributed to the construction of the technological backbone of the new infrastructure.

A smart tram network

SIR2 (Sistema Intermedio a Rete - Intermediate Network System) represents the second axis of the future SMART tram network, designed to connect Rubano, the centre of Padua and Vigonza through approximately 16 kilometres of line. Included in the Urban Sustainable Mobility Plan, the project will complement the SIR1 and SIR3 lines to create an integrated network converging at the railway station hub, promoting intermodality between rail, tram, bus and active mobility.

Lot 2 covers the eastern section of the infrastructure, extending for approximately seven kilometres from Padua railway station to the Busa di Vigonza terminus, with a branch towards the future Padua East Hospital. The project also includes the upgrading of the existing Guizza Depot through the construction of a new depot building, fully equipped with all the systems required to safely keep the trams energised, as well as the implementation of a centralised Smart management system for the three SIR lines.

The SIR2 route runs entirely through an urban environment, crossing some of the city's main activity hubs and operating predominantly on a dedicated right-of-way to ensure operational continuity, reliability and service regularity. Its construction preserves the continuity of road traffic, underground utilities and urban activities, requiring careful planning of the construction phases and constant coordination between civil works, trackwork and technological systems.

Platform and Trackwork: the Precision of the Monorail

In the Translohr system adopted for SIR2, the vehicle does not run on two rails as in a conventional railway but travels on rubber tyres while maintaining its trajectory thanks to a single central guidance rail engaged by four inclined guide rollers installed on each axle of the vehicle. This solution allows minimum curve radii of just 10.5 metres, enabling the line to be integrated even into the most complex urban environments while maintaining high levels of comfort and safety.

For this reason, in the Translohr system the platform is the key structural element of the infrastructure. GCF constructed a continuous reinforced concrete slab (C35/45), forming the support for the entire system. Measuring 2.20 metres in width and 25 centimetres in thickness, it provides high rigidity, long-term stability and extremely tight geometric tolerances.

Integrated within the slab is the recess accommodating the guidance rail, 20 centimetres wide and 8 centimetres deep, embedded into the pavement and aligned with the rolling surface with millimetric tolerances.

"The trackwork is one of the most technologically innovative elements of the project," explains Fabrizio Carnevali, GCF Technical Director. "The installation of the central monorail and its fastening using elastomeric resin required extremely high-precision workmanship. The permitted tolerances between the tyre rolling surface and the rail head are in fact only a few millimetres. Even the groove-filling profile surrounding the rail was specifically designed to ensure maximum fastening while providing the optimum functional clearance for the guide rollers, as well as the best possible electrical insulation and vibration isolation of the rail."

The surface finish also contributes to the functionality of the infrastructure. Throughout the urban sections, the platform was constructed with its characteristic red colouring to visually identify the dedicated tramway right-of-way and, along its entire length, underwent a surface treatment to ensure high skid resistance.

Electric Traction: Power Distributed Along the Entire Line

The system is powered by an overhead contact line specifically designed for the Translohr system. The contact line consists of a single hard-drawn, shaped copper contact wire with a cross-section of 120 mm² running along the centreline of the track. It is supported by 640 Mannesmann poles or H-type masts, equipped as required with cantilevers, flying steady arms, cross-span arrangements and flexible portals. The electric traction installations are completed by support structures, sectioning and earthing systems, together with stray current protection measures.

Power supply to the trams — at a nominal voltage of 750 V DC — is ensured by a network of electrical substations that transform and distribute energy along the entire route, guaranteeing operational continuity and infrastructure reliability.

Infrastructure Looking to the Future

With Lot 2 of SIR2, Padua takes another step towards increasingly sustainable, integrated and intermodal urban mobility, capable of meeting a transport demand estimated at 20 million passengers per year by 2030.

"This project," emphasises Giuseppe Brecciaroli, Chief Executive Officer of GCF, "demonstrates GCF's ability to operate as a system contractor in tramway infrastructure, integrating civil works, trackwork and electric traction systems into a single construction process. This combination of expertise represents one of the Group's key strengths in the delivery of high-technology public transport systems."

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