Bonded insulated joints in rails separate electric circuits in tracks and turnouts. As they are used in continuously welded rails (CWR), they must be able to transfer longitudinal forces arising in the track. Insulated joints with square cut and with angular cut are available.
Generally, they are supplied as pre-fabricated joints glued into short rail pieces. Insulated joints with square cut can also be made in the track.
If bonded insulated joints are used, the track must meet certain requirements regarding stability, good tamping and sleeper quality. A non-bonded insulated joint is a disturbing factor in the continuously welded rail, therefore bonded insulated joints are used with four or six bolts.
All insulated joints are checked for their electrical resistance. If a high number of joints is supplied, even destructive tests like tensile test and fatigue tests are conducted.
The insulated joint consists of two separated rail pieces, two steel fishplates, the corresponding number of high-tensile bolts, insulating pads, insulating bushes and end posts made from synthetic material and glass fibre mats.
| Types of sleepers | Wood and concrete |
| Rail sections | All common rail sections |
| Heat treatment of the joints | Hardened or preferably made from head-hardened rails |
| Bonding | With appropriate bonding and hardening agents |
| Manufacturing locations | In the factory: Ideal conditions regarding cleanness, temperature and manufacturing procedure because the rail ends and the surface of the steel parts to be bonded must be spotlessly clean At site: If the instructions of the supplier are followed |
