Transporting plant machinery such as tractors and agricultural machinery can be a highly complex and challenging manoeuvre and requires dedicated trailers and vehicles to carry out such tasks. Plant trailers vary, so specific trailers can be used for different types of loads. Each type of trailer has to meet very stringent technical requirements in order to be used safely and effectively. Using the wrong type of trailer or using a trailer incorrectly can have serious safety consequences
Types of trailer
There are at least a dozen different types of plant trailers, some of which are enclosed and are used to carry very specific machinery. The three most common types of plant trailer are known as a pig trailer, a dog trailer and a semi-trailer. The pig trailer has one set of wheels fitted to the middle of the trailer, which suits certain types of goods or loads. The dog trailer has two sets of axle-based wheels, one at the front and one at the rear, which provide greater stability. A semi-trailer has one set of wheels at the rear of trailer, with the front end attached to the vehicle drawing it. This type of trailer is designed to spread the load more evenly between the trailer and the supporting vehicle.
An enclosed trailer will have a very specific purpose. It will be intended to be used as a mobile home or an office or to provide sleeping accommodation at a construction site. Some types of enclosed trailers are referred to specifically as plant trailers, such as a concrete mixer or a drilling rig.
A number of trailers are designed specifically to carry certain types of equipment or vehicles, such as cars, boats and horses or other types of livestock. While not technically plant trailers, they might well be used in addition to specific types of plant and machinery that will be transported at the same time.
There are essentially three categories of trailers: a very light trailer, a light trailer, and a medium trailer. The importance of categories is that they are defined by their tonnage, which determines the maximum load that they can be used to transport. There are also definitions within these categories of width and length of the trailer, which must be taken into account when deciding what type of trailer is used for any equipment that needs moving.
Lighting is perhaps the most crucial element of the technical requirements for a plant trailer. There are approximately 12 or 13 different positions where lights have to be fitted on most trailers, and there are specific requirements for each type of lamp, and the position where it is to be fitted. In addition to the front and rear of the trailer, lights also have to be fitted to the indicators, the sides of the trailer, the hazard warning lights and, most importantly, the reversing lamps. There are very specific requirements as to what colour the lights have to be, ranging from red to amber to white. All lighting has to conform to specific ECE regulations and has to be fitted correctly in terms of their position and alignment.
In addition to the importance of lighting, the electrical wiring has to be fitted in such a way that it cannot in any way be damaged by either the load that is being carried or by the nature of the trailer itself. This means there must be very defined intervals where it is insulated, and the wiring must be placed in positions where it cannot overheat and where it completely avoids any moving parts of the trailer or vehicle.
Depending upon the environment and time of year the trailer is being used, it may well be necessary to fit some type of safety chain to it. This is determined by the type of trailer being used and whether or not it has any independent braking mechanism.