A data center build runs on dated milestones. The electrical room needs switchgear. The white space needs CRAC and CRAH units before commissioning. The pad needs the transformer. Every one of those pieces moves on open deck freight, and height and weight decide the trailer before price does.
Rockwall Services has brokered freight since 2009 and handles data center critical-path freight across all 48 contiguous states, Mexico, and Canada. We are asset light, so we place your equipment with vetted carriers. This page covers the trailer choice, the legal limits, securement, and what a broker needs to quote the move.
Deck height decides the trailer
Open deck trailers differ mainly in how far the deck sits off the road. That number decides whether your equipment travels legally or travels on a permit.
| Trailer | Typical deck height | Usable for |
|---|---|---|
| Flatbed | About 60 inches | Racks, cable reels, conduit, steel, palletised gear under about 8 feet 6 inches tall |
| Step deck | About 60 inches upper, 38 to 42 inches lower | Equipment to roughly 10 feet tall, including many CRAC and CRAH units |
| Double drop | About 18 to 24 inches in the well | Tall switchgear lineups and cooling towers that exceed step deck clearance |
| Removable gooseneck (RGN) | About 18 to 24 inches in the well, with a detachable front | Heavy transformers and gear that must be rolled or driven on rather than craned |
Flatbeds load and tarp fast from either side. Step decks buy roughly 20 inches of height for the same ease of loading. Double drops trade well length for clearance, so the well becomes the constraint on long assemblies. An RGN adds drive-on loading and a higher weight rating at a higher rate. Choose by the equipment, then confirm the deck or well is long enough.
The loaded height math
Loaded height is deck height plus equipment height. Do the arithmetic before you request a quote, because it decides your permit exposure. Work it in three steps:
- Measure the equipment as it will ship. Include the crate, the skid, the pallet and any protective frame. Crating routinely adds four to eight inches under a unit.
- Add the deck height of the trailer you are considering. Convert everything to inches so nothing gets lost.
- Compare the total to 13 feet 6 inches, the height most states allow before a permit applies.
A worked example. A CRAH unit measures 9 feet 8 inches tall on its skid. On a 60 inch flatbed deck it loads to 14 feet 8 inches, over the common limit, so it needs a permit and a route survey. On a step deck with a 40 inch lower deck it loads to 13 feet and stays legal in most states. Same equipment, different paperwork and lead time.
Where a legal load becomes an oversize load
Federal rules set the baseline on the Interstate System. The Federal Highway Administration enforces a maximum width of 8 feet 6 inches, a gross vehicle weight of 80,000 pounds, a single axle limit of 20,000 pounds, and a tandem axle limit of 34,000 pounds. Axle spacing is governed by the Federal Bridge Formula, so a legal gross weight can still fail if the load sits wrong on the trailer.
The states set height and length themselves. A ceiling of 13 feet 6 inches applies across most of the country, and several western states allow 14 feet. Two things follow, and both hit your schedule:
- State limits vary and permits are state specific. A load that runs legally through Texas can require a permit at the next state line. Every state on the route issues its own permit, sets its own fee, and can restrict travel to daylight hours, weekdays, or specific corridors.
- Permits take time. Build permit lead time into the milestone date rather than the dispatch date.
If your equipment passes any of these thresholds, read our guide to oversize load permits and escorts before you lock the delivery window. For how these moves fit the build schedule, start at our data center logistics overview.
Securement and tarping for sensitive equipment
The FMCSA cargo securement rules set minimum tiedown counts by cargo length and weight, and require the aggregate working load limit of the tiedowns to reach at least half the cargo weight. That is the floor. Data center equipment usually needs more. Ask these questions before dispatch:
- Where are the lift points and the tie points? Manufacturers mark them for a reason. Chaining across a cabinet frame or a cooling coil bends what it touches.
- Does the load need edge protection and softeners? Bare chains and straps mark painted enclosures and crush crate corners.
- How is the load tarped? Steel tarps and lumber tarps are different sizes. Tall crated equipment often needs a smoke tarp arrangement or a full enclosure, and the tarp itself adds height.
- Are shock or tilt indicators required? Transformers and switchgear frequently ship with impact recorders that void a warranty claim if they trip.
Why equipment ships crated or shrink wrapped
Manufacturers crate or shrink wrap electrical and mechanical assemblies to control three exposures. Moisture is the first. Windings, control boards, coils and bus bars corrode under a wet tarp, and sealed crating with desiccant holds that off. Shock and vibration are the second. Road input loosens fasteners, cracks porcelain bushings and shifts internal assemblies, and blocking inside a crate pushes that energy into the crate structure. Handling damage is the third. A crate gives a rigger a surface built to be touched.
Tell your broker what the packaging is, because it changes the quoted dimensions, the tarping plan and the securement plan.
What a broker needs to quote it accurately
A quote holds at the dock when it was built on real numbers. Send these with the request:
- Dimensions and weight for each piece, measured as packaged
- Centre of gravity, and whether it sits off the geometric centre
- Marked lift points and tie points, or the manufacturer’s rigging drawing
- Packaging type, crated, shrink wrapped, or bare on a skid
- Origin loading method and equipment available, dock, forklift capacity, or crane
- Destination site access, gate width, turning radius, ground conditions, and whether a crane is on site
- The required delivery date and any commissioning sequence tied to it
Centre of gravity and lift points get left out most often, and they are the two that change the trailer, the axle plan and the permit. Supplying them up front is how a rate survives the trip.
Rockwall Services brokers this freight under USDOT 2628509 and MC 907777, with vetted carriers and quotes that hold up at the dock. Our traditional freight brokerage covers individual moves, and our global supply chain service covers equipment arriving from overseas suppliers.
Frequently asked questions
What trailer do I need for a 10 foot tall CRAC unit?
Measure the deck height first. A standard flatbed deck sits near 60 inches, so a 10 foot unit loads to roughly 15 feet and needs a permit. A step deck lower deck near 40 inches brings the same unit to about 13 feet 4 inches, which clears the common 13 foot 6 inch limit.
When does data center equipment become an oversize load?
Federal rules govern the Interstate System at 8 feet 6 inches wide and 80,000 pounds gross. Most states hold height at 13 feet 6 inches and set their own length rules. Cross any of those and the move needs a permit. Limits and permits are state specific, so the routing decides the paperwork.
Should switchgear ship crated or open on the deck?
Ask the manufacturer. Sensitive electrical and mechanical assemblies usually ship crated or shrink wrapped because the packaging controls moisture, dust and handling damage. The packaging also changes the securement plan, the tarping plan and the dimensions we quote, so tell your broker what the equipment leaves the plant wearing.
What does a broker need from me to quote an open deck move accurately?
Send dimensions and weight per piece, the centre of gravity, marked lift points, the packaging, the origin and destination site access, and the required delivery date. Missing centre of gravity and lift points is the most common reason a quote changes after dispatch. Call Rockwall Services at 972-685-6993 with the packing list.
Talk to us before the equipment ships
Send the packing list and the site access details, and we will tell you which trailer class the move needs and where the permit exposure sits. Call 972-685-6993 or email contact@rockwallservices.net.