What is a double stack train?

A double stack train is a freight train that carries intermodal shipping containers stacked two high on specialized rail cars, effectively doubling the cargo capacity of the train.

Why is double stacking not common in Europe?

Double stacking is rare in Europe due to restricted infrastructure limits (loading gauge). Historical tunnels, low bridges, and overhead power lines (catenary) are generally too low to accommodate the height of two stacked containers.

A well car is a specialized railway wagon with a depressed center section. This design sits the bottom container lower to the tracks to reduce overall height and improve stability for double stack transport.

The Vertical Revolution: Double Stack Rail Transport Explained

Maximize freight efficiency with Double Stack rail. Discover how stacking containers vertically doubles train capacity and why infrastructure limits its global adoption.

December 11, 2025 5:58 am

What is Double Stack Rail Transport?

Double stack rail transport is a form of intermodal freight transport where railroad cars carry two intermodal containers stacked one on top of the other. Introduced in North America in the late 1970s, this method effectively doubles the cargo capacity of a train without increasing its length, revolutionizing the economics of rail logistics.

The Role of the “Well Car”

The key technology enabling double stacking is the Well Car (or double-stack car). Unlike a standard flatcar, a well car has a depressed center section (the “well”) situated between the wheel bogies. This design serves two critical purposes:

Clearance: It lowers the bottom container closer to the tracks, reducing the overall height of the stack to fit under bridges and tunnels.
Stability: It lowers the center of gravity, ensuring the train remains stable around curves despite the increased top weight.

Economic and Environmental Benefits

Double stacking is the most efficient method of moving freight over land. By carrying twice as many containers per train, operators drastically reduce the cost per container-mile. This efficiency also translates to environmental gains; a double-stack train is significantly more fuel-efficient per ton of cargo compared to trucking or single-stack trains.

Comparison: Single Stack (COFC) vs. Double Stack

Feature	Single Stack (Standard)	Double Stack
Capacity	1 Container per wagon length	2 Containers per wagon length
Wagon Type	Flatcar	Well Car
Height Clearance	Standard (fits most tunnels)	High (approx. 6.15m / 20.2ft)
Dominant Region	Europe, Asia (Standard lines)	North America, India (DFCC)

Why Isn’t It Everywhere?

While highly efficient, double stacking requires specific infrastructure. The combined height of two “High Cube” containers is significantly taller than standard rail clearances.

In Europe, widespread adoption is limited because many historical tunnels are too low, and overhead electric lines (catenary) obstruct the extra height. Conversely, North America’s vast diesel-powered network with generous loading gauges is ideal for this method. However, countries like India are now building dedicated freight corridors specifically designed for double-stack electric trains using high-reach pantographs.