What does EOT crane mean?
EOT crane stands for Electric Overhead Travelling crane. It is an overhead lifting machine in which a bridge spans a building bay, travels along two elevated runway beams, and carries a hoist that lifts the load. The "electric" means the long-travel, cross-travel and hoisting motions are all powered by electric motors rather than moved by hand; the "overhead travelling" means the whole crane runs over the floor on a fixed runway, keeping the working area below clear. In Australian industry the term EOT crane is used interchangeably with overhead bridge crane — they describe the same machine.
The full form is worth unpacking because each word is a specification. A hand-pushed or chain-operated bridge crane is technically not an EOT crane; it becomes one once the travel and hoisting are motorised and electrically controlled. The overwhelming majority of overhead cranes supplied to Australian workshops, fabrication shops, mines and process plants today are EOT cranes.
Is an EOT crane the same as an overhead bridge crane?
For practical purposes, yes. "Overhead bridge crane" describes the structure — a bridge girder running on a runway. "EOT crane" describes the same structure with the added detail that it is electrically powered and travels under its own motors. A double-girder box crane lifting 30 t in a steel mill and a 2 t single-girder crane in a maintenance bay are both EOT cranes and both overhead bridge cranes. The terms are interchangeable, and you will see both used on the same quote.
The distinction only matters at the margins. A monorail hoist running on a single fixed beam, or a manually-traversed bridge, sits outside the strict EOT definition because there is no powered bridge travel. Once a powered bridge travels on a runway, "EOT crane" and "overhead bridge crane" mean the same thing.
The parts of an EOT crane
Every EOT crane is built from the same core assemblies, whatever its capacity. Understanding the parts makes the rest of the specification — and the points where a crane is most often got wrong — much clearer.
- Bridge (main girder): the beam, or pair of beams, that spans the bay and carries the hoist. It can be a rolled I-beam or H-beam on lighter cranes, but is most commonly a fabricated box girder.
- End carriages (end trucks): the assemblies at each end of the bridge that house the travel wheels and the long-travel drive. They carry the bridge along the runway.
- Runway: the two parallel beams, supported by the building structure or dedicated columns, on which the crane travels the length of the bay. The runway is part of the lifting system and must be engineered to the crane's wheel loads.
- Trolley (crab): the unit that traverses across the bridge, carrying the hoist from one side of the bay to the other.
- Hoist: the wire-rope or chain hoist that raises and lowers the load. Sorian supplies hoists as bought-in components matched to the duty rather than manufacturing them.
- Controls: a pendant pushbutton station hanging from the crane, or a radio remote, giving the operator command of all three motions. Radio remotes are also supplied to suit, not manufactured in-house.
The three motions — long travel (the bridge along the runway), cross travel (the trolley across the bridge) and hoisting (the load up and down) — together let the hook reach almost any point in the rectangular volume under the runway. That full-bay coverage is the reason an EOT crane is the most efficient way to move loads across an entire facility.
Single girder vs double girder EOT cranes
The first configuration decision is how many bridge girders the crane has, and it follows from capacity, span and required hook height.
A single-girder EOT crane has one bridge beam, with the hoist hanging beneath it on an underslung trolley. It is the more economical configuration, needs less headroom, and is lighter on the runway and supporting structure. Single girder suits light to medium duty, typically from 500 kg up to around 20 t, with the 15–20 t band being the engineering-judgement zone where the call depends on span, duty and headroom.
A double-girder EOT crane has two parallel bridge beams with the trolley and hoist riding on top, between the girders. This raises the hook height for a given building, carries heavier loads over longer spans, and copes better with high duty cycles. Double girder is generally the call above roughly 20 t, and is preferred wherever maximum hook-on height or a long span is needed. It is heavier and more expensive, so it is specified when the duty genuinely requires it, not by default.
| Capacity | Single girder: 500 kg to ~20 t · Double girder: typically above ~20 t |
| Headroom | Single girder needs less · Double girder gives a higher hook |
| Span | Double girder handles longer spans more comfortably |
| Duty | Double girder preferred for heavy, continuous cycles |
| Cost | Single girder is the more economical configuration |
Top-running vs underslung EOT cranes
The second configuration decision is how the crane sits on its runway. The two arrangements are top-running and underslung.
In a top-running EOT crane, the end carriages ride on rails fixed to the top of the runway beams. This is the standard arrangement for higher capacities and longer spans because the runway can be sized and supported independently of the crane, and it suits the full single-girder and double-girder capacity range.
In an underslung (under-running) EOT crane, the end carriages run on the bottom flange of the runway beams, so the crane hangs beneath the runway. Underslung cranes are typically limited to lighter capacities but make excellent use of low-clearance buildings and allow the runway to be hung from the roof structure, which can also enable multi-bay coverage and easier interbay transfer. The trade-off is that the building roof structure has to carry the loads.
Duty class: the spec that is most often left off
The single most important number on an EOT crane specification is the duty class, and it is the one most often omitted from a catalogue quote. The duty class combines how often the crane lifts (its load frequency, or number of working cycles over its life) with how heavy the typical lift is relative to rated capacity (the load spectrum). Together these tell the designer how hard the crane will be worked, and they drive the fatigue design and structural sizing.
Set the duty class too low for the actual operating cycle and the crane will burn through brakes, contactors, gearboxes and wire ropes years ahead of its rated life, and the structure becomes a candidate to fail its 10-yearly major inspection. Set it too high and you pay for steel and mechanism you do not need. Two cranes of identical rated capacity can require very different structures because they sit in different duty classes. The class is an engineering assessment of how the crane will actually be used — not a catalogue default. See crane duty classes for how the M and A classes are set.
Capacity is always MRC, and the standards that apply
The rated lifting capacity of an EOT crane is its Maximum Rated Capacity (MRC) — the heaviest load the crane is designed and certified to lift. Every EOT crane Sorian supplies is engineered to AS 1418, the Australian Standard for the design of cranes, hoists and winches, which governs the structural, mechanical and electrical design including the duty classification. Once in service, the crane is inspected and maintained under AS 2550, which covers safe use, inspection regimes and the periodic major inspection. Larger cranes may also require design registration with the relevant state regulator. Specifying to AS 1418 and maintaining to AS 2550 is what keeps an EOT crane both legal and reliable across its design life.
When an EOT crane is the right choice
- You need to move loads across an entire building bay, not just a single workstation.
- There is a building structure or room for columns that can carry a runway.
- Lifts are frequent or heavy enough to justify powered travel and hoisting.
- You want full rectangular hook coverage rather than the arc of a jib crane.
Where there is no overhead structure to support a runway — open yards, leased premises, low-clearance buildings — a gantry crane is often the structurally simpler answer. For point-of-use lifting at a single station, a jib crane usually suits better. An EOT crane earns its place when full-bay coverage and powered, repeatable lifting are what the work demands.
Limitations to keep in mind
An EOT crane is a fixed installation: it covers the rectangle under its runway and nothing beyond it, so it cannot service areas the runway does not reach. It depends on a runway engineered to its wheel loads, which means the building or columns have to be assessed and sometimes upgraded — a cost that catalogue pricing often hides. And because the duty class drives the design, a crane bought on capacity and span alone, with the duty cycle guessed, can be quietly mismatched to the work until wear or an inspection reveals it. None of these are reasons to avoid an EOT crane; they are reasons to have the runway and duty assessed properly before you buy.
Talk to an engineer
An EOT crane is sized from your bay, your capacity and your actual duty cycle — not from a catalogue line. We assess the runway, set the duty class in writing, and specify the right single-girder or double-girder, top-running or underslung configuration for the work. Send through your application details and we will tell you what the job actually needs.
Frequently asked questions
What does EOT crane stand for?
EOT crane stands for Electric Overhead Travelling crane. It is an overhead lifting machine whose bridge is motor-driven along an elevated runway and whose hoist is electrically powered, so the long-travel, cross-travel and hoisting motions are all driven by electric motors rather than moved by hand.
Is an EOT crane the same as an overhead bridge crane?
Yes. In Australian industry the terms are used interchangeably. "Overhead bridge crane" names the structure — a bridge running on a runway — and "EOT crane" adds the detail that it is electrically powered and travels under its own motors. The same machine is correctly called by either name.
What are the main parts of an EOT crane?
The core parts are the bridge (main girder), the end carriages that carry it along the runway, the runway beams themselves, the trolley or crab that traverses the bridge, the hoist that lifts the load, and the controls — a pendant pushbutton station or a radio remote. The hoist and radio remote are supplied as bought-in components matched to the duty.
What is the difference between single girder and double girder EOT cranes?
A single-girder EOT crane has one bridge beam with the hoist hanging beneath it; it is more economical, needs less headroom and suits capacities up to around 20 t. A double-girder EOT crane has two beams with the hoist riding on top between them, giving a higher hook, longer spans and heavier capacities, and is generally the call above roughly 20 t.
What standards apply to an EOT crane in Australia?
An EOT crane is designed to AS 1418, the Australian Standard for the design of cranes, hoists and winches, which sets the structural, mechanical and electrical requirements including the duty classification. Once in service it is inspected and maintained under AS 2550. Capacity is always stated as the Maximum Rated Capacity (MRC).
Related
- Overhead Bridge Cranes — the EOT bridge-crane product hub
- Single Girder Overhead Crane — the economical EOT configuration
- Double Girder Overhead Crane — higher-capacity EOT
- Top Running Overhead Crane — top-running EOT layout
- Crane Duty Classes — how M/A duty class is set