What is the difference between an RTG and RMG crane?

RTG and RMG are both port equipment gantry cranes used for stacking and retrieving containers in a container terminal yard. The fundamental difference lies in how they move: an RTG (Rubber Tyred Gantry) runs on rubber tyres and can be driven between different stack lanes, while an RMG (Rail Mounted Gantry) runs on fixed rails and cannot leave its designated lane without major civil works.

RTG — Rubber Tyred Gantry

An RTG straddles a row of container stacks and moves along the yard on large rubber tyres. The crane trolley travels along the gantry beam to position the spreader over the target container. RTGs can be re-positioned to a different stack lane by driving on the cross-travel path — giving terminal operators significant flexibility to adapt yard layouts without rebuilding infrastructure.

• Typical stack height: 1-over-5 (i.e. 6 containers high).
• Typical stack width: 6–10 containers wide (plus a truck lane underneath).
• Power: diesel-electric, hybrid, or electrically powered via cable reel or busbar.
• Automation: semi-automated and fully automated variants exist (ARMG = Automated RTG).

RMG — Rail Mounted Gantry

An RMG travels on steel rails embedded in the yard surface. Because the rail geometry is fixed, positioning accuracy is inherently higher than with rubber tyres — making RMGs the preferred choice for fully automated terminals where millimetre-level precision is needed for automatic container placement and AGV handoff.

• Typical stack height: 1-over-5 to 1-over-7 (higher than most RTGs).
• Typical stack width: up to 14 containers wide (larger footprint than RTG).
• Power: almost exclusively electric (rail-mounted infrastructure makes cabling straightforward).
• Automation: most modern RMGs are fully automated (ARMG).

RTG vs RMG: comparison table

Feature	RTG	RMG
Mobility between lanes	Yes — can cross-travel	No — fixed to rail lane
Positioning precision	Good (±50–150 mm)	Very high (±10–30 mm)
Civil works required	Low — flat yard surface	High — rail foundation and drainage
Stack density	Moderate	High (wider spans possible)
Automation suitability	Good (ARTG)	Excellent (ARMG)
Typical application	Flexible mid-size terminals	Large automated mega-ports

Which is right for your terminal?

RTGs are the right choice when flexibility matters more than density — for example, a terminal that handles seasonal peaks, serves multiple cargo types, or expects future layout changes. RMGs make economic sense for greenfield mega-terminals designed around full automation from the outset, where the higher civil investment is offset by lower long-term operating costs.

Browse port equipment on Portneeds: used and new RTG cranes for sale.