Why do trailers need their own register and inspection checklist?
A tractor has a driver, a fuel card and a trip log. A trailer often has nothing: it is dropped at a customer's site, swapped at a yard or left at a port, and its paperwork expires without anyone noticing. A trailer register gives each trailer one row with its documents and status. The coupling log records every hitch and drop, so when damage, a fine or a missing load turns up, you know which tractor and driver had the trailer at that time.
The trailer inspection checklist covers the points a tractor inspection misses: the kingpin and fifth wheel, air and electrical lines, landing gear, underrun bar, lashing points and, for reefers and tankers, the unit and the valves.
What should a trailer inspection checklist include?
The fourteen items in the file, grouped by area. Each gets Pass, Fail or N/A, and a severity for each Fail:
- Coupling: kingpin and fifth-wheel jaws locked, air lines and electrical cable connected without chafing, landing gear fully raised.
- Lights and marking: tail, brake, indicator and side lights; reflectors and rear marking plates.
- Brakes and tires: no air leaks, brakes apply and release; tread, damage, pressure and wheel nuts. Track tires in the Tire Management Log.
- Body and load: underrun bar and side guards, mudguards, twist-locks, lashing points and straps, doors, curtains and seals.
- Special trailers: reefer set-point, unit running and fuel; tanker valves and manlids closed and sealed.
- Documents: plate fitted, registration and inspection papers on board.
Severity has three levels: Stop (the trailer does not move), Fix within 24 h and Next service. One Fail with severity Stop makes the result "Fail: do not move".
How to use the trailer register, step by step
- Enter each trailer once in the register, with its three expiry dates.
- Log every coupling when a tractor picks up a trailer, and the uncoupling when it drops it. Leave "Uncoupled" blank while the trailer is still attached.
- Print the checklist for the pre-trip or weekly inspection, and record the result in the inspection log.
- Raise each defect in the defect log with a work order number from your maintenance work order, and close it with the repair date.
- Review the summary weekly: idle trailers, documents expiring, inspections due and open Stop defects.
How does the file calculate idle days and flags?
The coupling log also flags a trailer not in the register, a coupling without the pre-coupling check, an uncoupling time before the coupling time, a trailer already coupled to another tractor, and a coupling made while a Stop defect was open. The interval, warning and idle limit are example values on the Settings sheet.
Worked example: a lowbed and a curtain-sider
Six trailers, checked on 21 October 2026.
- Lowbed TR-14 was coupled to TRK-07 on 10 October at 05:40 in the Dammam 2nd Industrial City yard and dropped in Jubail on 11 October at 18:10: 36.5 hours and 108 km. It has stood since then: 9 days idle, above the 7-day limit. Its periodic inspection expired on 5 October, so the Documents column shows Periodic inspection expired.
- Curtain-sider TR-12 failed its weekly inspection on 14 October: a torn side curtain and damaged strap (Stop) and a brake light out (Fix within 24 h). It was coupled to TRK-03 the same morning with no pre-coupling check, so the coupling log flags Pre-coupling check not done; Open Stop defect.
- The summary shows 4 active trailers, 1 in the workshop and 1 idle, 2 coupled now, 2 open defects of which 1 is Stop.
Common mistakes with trailer records
- No coupling record. Without it, nobody can say who had the trailer when it was damaged or fined.
- Inspecting the tractor and assuming the trailer. Coupling, landing gear and lashing points need their own check.
- Trailer documents tracked with the tractor's. A trailer has its own registration, inspection and insurance dates.
- Coupling with an open Stop defect. Close the defect, or keep the trailer off road.
- Ignoring idle trailers. A trailer idle for weeks is capital you pay for and do not use.
- Defects without work orders. A defect with no work order number is rarely fixed on time.
What the template does not cover
Periodic technical inspection intervals and how long you must keep inspection records are set by your authority, and they differ by country and by trailer class: check your authority's current requirement and enter it in Settings. The checklist does not replace the trailer manufacturer's instructions or a workshop inspection. Load securing depends on the cargo; follow the securing method for your load. The template is a working tool, not legal advice.