FILE 04-B REV 2026.04 DRAFT
FRAME · 04-B / SEMI
04-B Section · Semi / Class 8
SEMI.CLASS 8.
Class 8 trucks already have an air system rated to 120+ PSI — adding a train horn is a tap, not a build. The hard part is choosing between an air-supplied chord horn that taps the factory wet tank, or an electric standalone for legal flexibility. Both have their place.
In the build queue
/01 PENDING
Tap factory air
Class 8 trucks already have 120+ PSI. Add a horn — it is a tap, not a build.
/02 PENDING
Air-supplied chord
Chord-style horns plumbed off the wet tank. Loudest, most authentic.
/03 PENDING
Electric standalone
Aftermarket electric for legal flexibility. Disable independent of air.
/04 PENDING
Sleeper-cab routing
Hood-mount vs cab-roof vs frame-mount. Heat and weather considerations.