A scenery wagon, also known as a stage wagon, is a mobile platform

Platform (theatre)

In theatre, a platform is a stationary, standard flat walking surface for actors to perform on. Typically, they are built to be assembled modularly. They are often used to provide varying levels, to make a show more visually interesting. They are also used to separate areas on stage, and as...

 that is used to support and transport movable, three-dimensional theatrical scenery

Theatrical scenery

Theatrical scenery is that which is used as a setting for a theatrical production. Scenery may be just about anything, from a single chair to an elaborately re-created street, no matter how large or how small, whether or not the item was custom-made or is, in fact, the genuine item, appropriated...

 on a theater stage

Stage (theatre)

In theatre or performance arts, the stage is a designated space for the performance productions. The stage serves as a space for actors or performers and a focal point for the members of the audience...

. In most cases, the scenery is constructed on top of the wagon such that the wagon, and the scenery it supports, forms a single, integrated structure. Heavy duty caster

Caster

A caster is an undriven, single, double, or compound wheel that is designed to be mounted to the bottom of a larger object so as to enable that object to be easily moved...

s are mounted to the underside of the platform so that the entire assembly can be quickly moved onstage or offstage, so as to facilitate rapid scenery changes during live productions. Scenery wagons are built in a wide range of sizes, ranging from less than one square foot up to the size of the playing area of the stage.

Scenery wagons comprise one of the four methods used to move scenery during the course of a theatre performance, the other three being "flying" (suspending) scenery from a fly system

Fly system

A fly system, flying system or theatrical rigging system, is a system of lines , blocks , counterweights and related devices within a theatre that enable a stage crew to quickly, quietly and safely fly components such as curtains, lights, scenery, stage effects and, sometimes, people...

, elevating or lowering scenery on a stage lift, or "running" (manually carrying) the scenery.

Casters

Various caster types are used on scenery wagons. The choice of caster type for any particular wagon depends on a number of factors, including platform size and shape, scenery weight, production aesthetics and budget. Typically, casters are mounted so that the bottom of the platform is elevated approximately one-half to three-quarters of an inch above the stage. The number of casters required for a wagon depends on caster type and load rating as well as the size, shape and weight of the wagon and scenery.

Swivel casters are commonly used on smaller wagons because of the flexible, mobility they offer. As the number of swivel casters attached to a wagon increases, though, it becomes increasingly difficult to align them. Consequently, it may be difficult or impossible to move a wagon that has a large number of swivel casters when the casters are unaligned. As a result, rigid casters are preferred for larger wagons, which typically require a proportionally higher number of casters.

Air caster

Air caster

An air caster is a pneumatic lifting device used to move heavy loads on flat, non-porous surfaces. Its operation is similar to a hovercraft, as it uses a thin layer of air as a way to float a very small distance off the ground...

s are sometimes used in place of rolling casters. These require pressurized air to operate, which produces audible hiss that is undesirable in some situations, and are typically more expensive than rolling casters, but they have the advantage of "locking" the scenery securely in place when depressurized and, like swivel casters, they permit omnidirectional movement.

Anchoring systems

To effect a scenery change, a wagon is simply rolled offstage to remove it from the set or rolled onstage to its designated position to add it to the set. In the latter case, the wagon must be immobilized after it has been positioned on the stage so that actors can safely interact with it (e.g., walk, stand, or jump on it) without causing the wagon to move. A number of methods and mechanisms are commonly used to immobilize, or "lock" scenery wagons in place:

Wedges

Wooden wedges may be forced between the stage and the bottom edge of the wagon perimeter. Ideally, the wedges are driven under the wagon to the extent that the wagon is supported by the wedges instead of its casters. Wedges are typically used in pairs, on opposite sides of the wagon so that the wagon can't slip off the wedges.

Slip bolts

Slip bolts may be used to hold scenery wagons in position when high lateral strength is required and it is permissible to drill holes in the stage. The bolts are mounted to the wagon base and, when the wagon is in position, the bolts are lowered into their designated, predrilled holes.

Lift jacks

A lift jack is fundamentally a lever

Lever

In physics, a lever is a rigid object that is used with an appropriate fulcrum or pivot point to either multiply the mechanical force that can be applied to another object or resistance force , or multiply the distance and speed at which the opposite end of the rigid object travels.This leverage...

 that attaches to the scenery wagon platform with a hinge

Hinge

A hinge is a type of bearing that connects two solid objects, typically allowing only a limited angle of rotation between them. Two objects connected by an ideal hinge rotate relative to each other about a fixed axis of rotation. Hinges may be made of flexible material or of moving components...

, with a caster mounted to the underside of the lever near the hinge. When no downward force is applied to the lever handle, the wagon rests securely on the stage; this effectively locks the wagon in place due to friction between the wagon platform and the stage. When the lever handle is forced downward, however, the caster serves as a to lift the wagon slightly above the stage, thus enabling the unit to be rolled.

Lift jacks may be built into a wagon or onto a wagon's exterior, as circumstances dictate.

Wagon brakes

A wagon brake

Brake

A brake is a mechanical device which inhibits motion. Its opposite component is a clutch. The rest of this article is dedicated to various types of vehicular brakes....

 has a handle which, when pushed down, extends a steel rod down and onto the stage. When fully extended, the steel rod actually lifts a section of the wagon slightly off the stage floor. The bottom end of the rod has a threaded cavity that will accept an extension spindle, which in turn can be used to adjust the height of the wagon above the stage. The brake is released by raising its handle, thereby retracting the steel rod away from the stage.

Wagon brakes provide a very fast means of locking and unlocking wagons, but the brakes and stage can be damaged if the running crew

Running crew

Running crew or run crew, is a collective term used in theatre to describe the members of the technical crew who supervise and operate the various technical aspects of the production during a performance...

 attempts to move a wagon while its brakes are engaged. Damage to the stage can be mitigated by using extension spindles with compliant (e.g., polyurethane) tips. Toggle clamps, which are functionally similar to wagon brakes, are sometimes used in lieu of theatrical wagon brakes due to their higher load ratings and more durable construction.

Hinged foot irons

Hinged foot irons may be bolted to the sides of the wagon. To lock the wagon in place, the free ends of the foot iron hinges are folded down and then secured to the stage with stage screws. This is a reliable method for immobilizing wagons, but it creates holes in the stage and can slow the process of locking and unlocking a wagon. Also, if a foot iron is allowed to contact the stage while the wagon is being moved, the stage floor can be damaged.