Tram Infrastructure Renewal Walchestrasse, Zurich

Walchestrasse forms part of the historic tram corridor linking Zurich Main Station, Walche Bridge and Stampfenbachstrasse. The route is one of the most important north–south connections within Zurich’s tram network and is used daily by several tram and bus lines. As part of the track renewal works on Walchestrasse, a new reinforced concrete track slab with rail embedment was constructed directly adjacent to Zurich Main Station. Due to the central urban location and the high traffic volumes, only a single weekend possession was available for the works. The line had to be fully reopened to regular tram operations by Monday morning.

Challenge

Urban rail infrastructure projects place demanding requirements on construction sequencing, materials and logistics. The available construction window was limited to a weekend closure, while multiple work stages had to be completed within a very short timeframe. In addition to achieving rapid strength development, the residual moisture content of the concrete was a critical factor. The waterproofing system and subsequent asphalt layers had to be installed only a few hours after concrete placement. Conventional concrete systems often reach their limits when such requirements must be met simultaneously.

Solution

Concretum^® Q-FLASH 5/20, a third-generation rapid-hardening concrete system specifically developed for time-critical infrastructure projects, was selected for the works. The concrete combines practical workability with very rapid strength gain and accelerated moisture reduction. This enabled both the construction of the track slab and the rail embedment works within the available possession period. Approximately five hours after placement, the required residual moisture level for the subsequent waterproofing application had already been achieved, allowing follow-on works to proceed without delay.

Result

The use of Concretum^® Q-FLASH 5/20 enabled all construction activities to be completed within the weekend closure. Rapid strength development and early waterproofing capability ensured an efficient construction process and the timely reopening of the tram line on Monday morning. The Walchestrasse project demonstrates how modern rapid-hardening concrete technology can significantly reduce construction times, minimise track possession periods and support the efficient delivery of complex urban infrastructure projects.