TwistLocks

Twistlocks are locking devices used in intermodal freight to secure containers during lifting, transport, and stacking. They engage the standardized corner castings found on intermodal containers, providing a reliable interface with handling gear such as crane spreaders, ship decks, railcars, and trailers. The corner fittings themselves are standardized under ISO 1161 to ensure compatibility across modes.

A twistlock typically consists of a base or mounting plate, a rotating locking element, and a release handle or actuator. During locking, the element is rotated 90 degrees, extending into a corner casting pocket and securing the container to the lifting or securing equipment. Some twistlocks are fixed to equipment; others are detachable or adjustable to accommodate different container lengths by configuring the locking height.

In typical operation, containers are moved with spreaders that engage the corner castings via twistlocks. When fully engaged, the twistlocks prevent vertical, horizontal, and angular movement during transport. A container is usually secured by four twistlocks at its corners, though configurations vary with equipment and mode.

Safety and maintenance: Twistlocks require regular inspection for wear, corrosion, or damage; locking pins or mechanisms must function correctly, and there should be established procedures for engagement and release. Damaged twistlocks are removed from service and replaced to maintain safe handling and transport.