Abstract: An enclosure system for a cargo truck can include one or more multi-purpose rails (e.g., top rail and/or bottom rail) to which components of the enclosure system (e.g., walls/curtains, cargo-securing accessories, etc.) can slidably attach. The enclosure system may include a frame that can attach to the flatbed, and the frame can include one or more multi-purpose rails that extend from one part of the enclosure to another part of the enclosure. The multi-purpose rails can include one or more channels, which can connect to components of the enclosure system and allow those components to be selectively secured in place or slid to another location within the enclosure system. The one or more channels can be configured to slidably receive an end of a support post and/or cargo securement components, which can be slid along the channels, from one part of the enclosure system to another part of the enclosure.