industries railTension Control Bolts are widely used throughout the rail network. Primary applications include new rail bridges, bridge strengthening, track joints / permanent way, temporary works, signal gantries and overhead line electrification (OLE).

Tension Control Bolts Ltd have the RISQs accreditation and are also accredited for rail station regeneration, station carparks, and stairwells and approved for use by Transport for London (TfL).

Rail Bridges

industries rail bridgesPermanent bolted connections of structural parts of bridge steelwork are almost always made with preloaded bolts in accordance with Network Rail Standards. Most connections are designed as category B (slip resistant at SLS) however category C (slip resistant at ULS) are chosen if oversized or slotted holes are required or where rigidity on a joint is required at ULS. Traditionally such connections have been known in the UK as High Strength Friction Grip (HSFG) connections however the more modern term in use is preloaded connection.

For short, medium and long-span bridges TCBs are preferred for site connections as bolting installation can be completed far more efficiently than welding or the installation of hexagon HV or HR assemblies.


TCB bolting assemblies are available in property class 10.9/10 with Greenkote corrosion protection but are also available in M24 and M30 diameter Weathering Grade Steel which meet the specifications detailed within EN 1090-2 section 5.6.6.

Our bridge projects include many examples of flagship rail bridges. If you are at the design stage for a new bridge, or looking at the maintenance and strengthening of an existing bridge please get in touch.

Rivet Replacement

The dome head of the TCB make it ideal for heritage structures where the appearance of the bridge needs to be preserved. In addition the characteristic dome head has a greater bearing surface against the steel. TCBs have been installed in the UKs longest rail bridge, the Tay Rail Bridge, and there are over half a million installed in the iconic Forth Rail Crossing (a UNESCO World Heritage Site) as rivet replacements.

Greenkote® anti-corrosion protection

Tension Control Bolts Ltd has its own metal coating plant producing an environmentally friendly process called Greenkote®, which is comparable to galvanising, although it is harder wearing and readily accepts all paint systems. Learn more about Greenkote.

Greenkote