Monorail Engineering

The United States Monorail and British Monorail divisions of AC-H Specialize in Monorail Systems.

Erector™ andRailmaster™ Monorails utilize component and custom design for economic production and erection of extremely large, complex systems. Application of current technology, coupled with innovative design, helps to produce state-of-the-art solutions to unique material handling problems.

Monorail systems are designed to carry material overhead, freeing up space on factory or production floors. Monorail systems can be designed to follow any pathway, around curves, through doors with door openers, branch out into separate lines with switches and turntables, interlock into overhead cranes etc. Monorails are either attached to the building structure or they can be free standing. Monorail systems are made up from the following parts: Monorail track, Trolleys, Tractors hoist, Switches, Turntables, and Lift drop Sections. Monorail systems can be manual or motorized, or any combination of the two. Monorail track can be made with our fabricated patented track or with standard I-beams. Our standard switches and turntables are made with patented track, but we can design an I-beam switch or I-beam turntable to match your particular I-beam.

Replacement parts are available for almost every Monorail we have ever built and can be sourced from the S.O. Number (Shop Order Number) found on the monorail Name Plate and on the user manual. Additionally, the invoice number can be used to identify the monorail.

Helpful Steps to Design A Monorail

(click to enlarge)

Sketch #1 Illustrates Required Measurements From The Overhead Structure To The Floor.

Step #1


  1. What is maximum weight of the load to the handled by the system including weight of hoist and rigging.
  2. What is maximum overall height of loads including slings, grabs or other hook attachments?
  3. How far above the floor mus hook height L be to assure free passage of load above any obstructions?
  4. How high above the floor ( support height C) are overhead structures from which the track will be suspended?
  5. To what and how will track hangers be attached overhead?
  6. How deep below floor level are pits or dock wells to be serviced?
  7. What are the clearance measurements R between overhead building obstructions such as pipes, ducts, or lights and the trusses or beams?

Step #2


ESTABLISH THE FOLLOWING: (1) the total load to be lifted, (2) hook height, and (3) lifting speed or speeds. Select a hoist load rating to equal or exceed total load weight.

Hook height or total lift height is the entire distance the hook must travel from the lowest point to the highest. In the sketch it is L.

Lifting speed or speeds are chosen to suit handling needs. You may want a two-speed hoist with fast lift speed and a slow speed for precise spotting.

When selecting a hoist, note its weight, also the distance H from hook throat to the rail ( the hoist headroom) when determining track height and hanger rod length.

Step #3


Establish the ECL (Equivalent Center Load) to be carried by the track and the span distance S between suspension points will determine the track size.

Maximum capacities between suspension points (S distance) are listed in the Load Chart Tables of available rails. Suspension points not exceeding maximum allowable spacing are selected to coincide with the overhead support structure. Track size is selected to coincide with the overhead support span and with capacities not below the ECL of the monorail.

Step #4


Match trolleys to the track and load requirements.

Larger wheel bases reduce the monorail ECL.

Step #5


(Refer to sketch page 1)

Where possible, use hanger assemblies with shortest available hanger rods. This will give maximum hook height and simple installation with minimum need for sway bracing.

Here we use all of the preceding steps to arrive at a working layout and prepare for Step # 6, a bill of materials for ordering.

The drawing below illustrates a typical monorail system with a main track, a switch and a spur track. Here is the field design data gathered per Step #1:

Required length of main line trusses A to I32'-0” approx.
Required length of spur under truss line E15'-0” approx.
Live load capacity1,000 lbs.
Desired lift speeds40 fpm – lift
10 fpm – creep
Desired hook height L10'-0”
Support height C14'-6”

The track is to be suspended form trusses of uniform support height except the switch and curve section which require jumper beams for support between trusses as indicated. Jumper beams are attached to trusses (see detail); hanger rod assemblies attached to them require extra length to keep track level.

System Layout

With the track size determined, actual layout begins. A place to start is the spur track with its switch. The fixed radius of the switch curve, location of the spur under truss line E and the 15′ spur length measured from the main track provide system reference locations. Switch specifications show the curve radius.

The switch accounts for part of the turn, a single curve section completes the 90 degree turn. The switch is drawn in tangent to line E and dimensioned. A section of straight track spliced in underline E completes the spur.

The main line track sections are seized for length after the suspension for the switch and spur is designed.

Switch and Spur Suspension Points

Suspension points for the straight section of the spur are from the track end and the splice end as shown. There are the minimum m and st dimensions for track as noted in Step # 3. The st dimension could be as long as 12” for the 10′ span W if the hanger must be adjusted to fall at a panel point on the truss (0.1 x W of 120”)

A 45° curve section must have one hanger in the center plus additional hangers near the splice in the connecting rails within the allowable st dimensions. When used with a switch, however, one of the hangers is required in the curve track adjacent to the switch splice.

Because these suspension points are located between the overhead trusses, jumper beams are required overhead for attachment of hangers.

Main Track Selection and Suspension

With the switch and spur in place on the layout, we look next at the 32′ of main track between trusses A and I. Allowable m cantilever dimension of 12”. An end stop complete that end.

Step #6

Hanger Rod Length ( See Step #5)

For this layout two different hanger rod lengths are necessary because all of the straight track is suspended directly from the trusses while the switch and the 45° curve are hung from jumper beams. The switch and curve hanger rods will be 4” longer than the straight track hanger rods because the bottom of the supporting jumper beam is 4” above bottom of truss.

To determine exact rod lengths, first determine hanger assembly lengths R1 and R2 per Step #5.

Straight Track R1

R1= C – (L + H + T) = 1′ -11 ¾”

Hanger Rod Length = R1 – 5”= 1′-6 ¾”

Cut rod from standard 24” length rod #982 288 NA

Switch and Curve Track R2

R2 = R1 + 4” = 2′ -3 ¾”

Hanger Rod Length = R2 – 5”= 1′-10 ¾”

Cut rod from standard 24” length rod #982 228 NA


Easily installed electrification track is available. The track serves as a support for the conductor bar assembly.

Self-aligning collectors travel with the load trolleys picking up power through spring-loaded shoes working in each conductor.

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