For the construction and refurbishment of rail structures, time is mostly of the essence, writes Simon Rickett, Regional Technical Sales Manager at Parex, a Sika Company…
Repairs or works that overrun can have serious financial implications for the rail company concerned, not to mention the detrimental effect it has on customers’ daily lives in terms of cancellations and delays. Contract rail works are often let on a short-term possession, typically one or two days over a weekend. Urgent repairs, however, are regularly carried out overnight during engineering hours, 11pm to 5am. Therefore, products that offer rapid solutions to issues varying in complexity are essential to servicers such as the transport sector.
Overnight re-setting of rail base plates
The type of urgent rail works that might require overnight, out-of-hours attention is anchor bolt replacement and base plate re-grouting. These are situated beneath the rail base plates, and their removal also requires the accompanying grout to be removed. Once the anchors have been replaced, the rail plates can be placed on top and levelled to the required height for the running rail. A secure shutter is then formed around the rail plate and grout is poured underneath to support it. Often, these shutters are pre-formed to a set size, which allows repeated use and saves precious time. A fast-setting grout, such as Parex’s Railfast Grout, an ultra-rapid, resin-based solution, means shutters can be removed soon after it’s been poured – within one to two hours. The site can then be cleaned down, debris removed and the line opened to rail traffic in time for the following morning’s commuters.
Railway station step free access programme
The Step-Free Access Programme, which has been taken on board by many stations throughout the UK, provides another example of general railway contract works. Instigated to achieve new standards of access for disabled passengers, the programme involves raising sections of platform to the same level as the train. In order to achieve this, contractors have been employed to remove platform tiles, excavate the supporting bedding mortar and build a new surface from the concrete base slabs.
Again, these works typically take place at the weekend with the station closed, or during a series of overnight shifts. To ensure work doesn’t overrun, the concrete used to build-up the platform has to work fast, which is where a solution such as Parex’s Tecfast Concrete is extremely helpful. When mixed, the product forms a flowing, pourable micro concrete with a 6mm aggregate that can achieve 20N/mm² compressive strength in just two hours. In such instances, the micro concrete is poured in sections into preformed shutters to the required depth and profile. Once sufficiently hard, it can either be left covered ready for further work the next night, or the tiles can be re-bedded and set for opening.
Rail train shed maintenance depot
On some projects it is possible to have extended programmes of work where multiple operations are carried out, such as in train maintenance depots. In these instances, trains are brought in for repair and need to be lifted. This can require the formation of level jacking pads. These are then placed on a series of base pads, which need to be sufficiently high-strength and level in order to lift the carriages. Steel shutters are formed to give a precise level to the top within +/- 2mm. Once set up at 30mm-to-50mm deep, the pads can be cleaned and made grout-tight, then poured in one operation using Parex E33 Epoxy Grout. This epoxy resin-based solution can achieve 63N/mm² compressive strength in one day, meaning shuttering can be removed and the train raised the following day.
Case study: Euston station refurbishment
A floor refurbishment at Euston station in central London, which was carried out by the Everlast Group using products supplied by Sika, offers an example of how new technologies have been used to speed-up rail station works to dramatic effect.
The repairs involved transforming a highly trafficked 300m2 ramp area of the station in just one weekend. More than 120,000 people pass through Euston on a daily basis. Therefore, contractors had a mere 48 hours to ensure the floor would be installed and ready for the weekday commute in order to minimise disruption for passengers and many station-based businesses.
The new system was to be laid directly over a tiled substrate which was showing signs of damage and wear due to sheer volume of foot, and occasional vehicle traffic. Everlast was required to remove loose or damaged tiles and build-up, and repair cracks or breaks in the surface using Sikadur® – a high-performance, high-precision strength, moisture-tolerant, epoxy grouting system. This solution eliminates dust production to significantly speed-up floor installation times. It was then over-coated using Sikafloor® Pronto – a fast-curing solution even at low temperatures. Pronto systems have a high resistance to a wide variety of uses, whilst the super-quick setting time of these synthetics allows for rapid refurbishment.
Their proven high-performance advantages also add long-term value for the client, as they have a static and dynamic bridging capacity; good impact and wear resistance; good chemical resistance; suitable for dry and wet conditions, and are impermeable to liquids etc.
Commenting on the Euston station floor refurbishment, a spokesperson for the terminus, congratulated Everlast on ‘a great job done’. ‘Our customers have really appreciated this piece of work’ the spokesperson said.
As the Euston station project demonstrates, by using quality repair and refurbishment systems, contractors can have the best of both worlds – speed and accuracy. It’s a formula for success that will help keep trains and their passengers on the rails.