Installing concrete slabs on the railway tracks at Almeda station owned by the Catalan railway company Ferrocarrils de la Generalitat

The FGC Almeda station, with trains bound for L’Hospitalet de Llobregat, needs to be renovated and have the existing ballast replaced with concrete slab. To do this work, one of the tracks will have to remain fully out of service and the other one kept operational. 

Crews will work non-stop, 24/7, including holidays. The track kept operational on the night shift is used to load and unload materials, auxiliary equipment, tools and waste. 

After the first track is taken out of service, workers begin replacing ballast with concrete slabs. This is a two-stage process, with each track replacement representing one stage. 

At night, the track is taken out of service, and the rails on the track being replaced are lifted and removed. Then the ballast bed is stripped, and metal formwork is applied to retain the ballast shoulder and stop the adjacent operating track from becoming uneven. This formwork will retain the existing ballast on the adjacent track and will be attached to the inverted arch using rebar and epoxy resin. 

Since the adjacent track is in service, a metal clearance safety barrier will need to be installed to ensure crews on the non-operating track can work safely. This barrier will be made of metal piping equally spaced 3 m apart, and galvanised metal mesh set 2.4 m high.

Day crews will clean the concrete slabs, and attach the connectors flush to the existing slabs using 20 mm rebar. Any cracks or crevices found on the slab are repaired with staples or injected with resin and defects are corrected using high strength grade mortar.  

Day crews also attach connectors to core walls using rebar, drilling and resin, and injection pipes and a hydro-expansive profile are laid down to waterproof the inverted arch.  

Once this work is finished, the structural slab is reinforced, formwork is applied along the shoulder, and after being primed with binder resin, concrete is poured for the new slab. The vents next to the Almeda station are used during this stage of the work. 

After the concrete is poured for the structural slab, the night crew will deal with the logistics side of supplying materials and tools and distributing rails and fasteners for assembling the new track on concrete. Once the new track is assembled and level, binder resin is used for different aged concrete, and concrete is poured for the track slab using MC-40 fibre concrete. Finally, the rails are welded, and once the concrete reaches FGC-required strength levels, the track is put into service and the other track is taken out of service.