Two Designs, Two Different Missions
The curtainsider and the refrigerated (reefer) trailer are the two most common enclosed-body solutions in road transport, yet they are built for entirely different purposes. The curtainsider is optimised for loading flexibility; the reefer is optimised for protecting cargo temperature. The right choice always follows the nature of the load.
The Curtainsider
On a curtainsider, the side walls of the body are not fixed panels but tarpaulin curtains sliding on rails. When the curtains are drawn back, the whole side of the deck becomes accessible.
- Loading is possible from the side, the rear and — on curtain-roof versions — from the top; forklifts and cranes work easily.
- Well suited to general cargo: pallets, coils, long profiles, building materials.
- The body is comparatively light, which benefits payload.
- Purchase and maintenance costs are lower than a reefer's; there are few moving parts.
- Its limit is clear: there is no temperature control, and a curtain seals less tightly than a rigid body. Perishable food or pharmaceuticals are out of its scope.
The Refrigerated Trailer
A reefer combines a closed body of insulated sandwich panels (typically polyurethane-cored) with a cooling unit mounted on the front wall. It is designed for temperature-sensitive cargo: perishable and frozen food, pharmaceuticals, certain chemicals.
- The set temperature is maintained throughout the journey; multi-compartment versions can run different temperature zones.
- In cold-chain transport, international rules (such as the ATP agreement) define equipment classes and periodic testing.
- Loading is normally through the rear doors only; there is no side access, which requires dock-based operations.
- The insulated body and cooling unit add weight, so payload is lower than a curtainsider's.
- Purchase price, fuel or energy consumption and cooling-unit maintenance raise the total cost of ownership.
The Cost-Flexibility Trade-off
The essence of the comparison: the curtainsider offers high operational flexibility at low cost but gives no temperature guarantee; the reefer delivers that guarantee at the price of extra weight, extra investment and extra running costs.
- If the cargo is insensitive to temperature, running a reefer simply burns money.
- If the cargo is perishable, running a curtainsider puts the load itself at risk — there is no saving in that scenario.
- For finding return loads, the curtainsider addresses a wider freight pool; the reefer, in turn, usually commands higher rates in the cold-chain market. Actual rate levels vary by market and season.
Which One to Choose?
There is no single winner; the decision follows the cargo. General cargo, palletised industrial goods and mixed part-loads point to the curtainsider; food, pharmaceuticals and anything temperature-sensitive point to the reefer. Carriers that keep both types in their fleet gain the flexibility to serve different freight segments at once.
Barlas Trailer manufactures and repairs both curtainsider and refrigerated trailers.