A ballast tractor
is a heavy road vehicle made to pull or push very heavy and large loads. It is intended
for transformer hauling and other super loads from a draw bar. The name ballast
is taken from the nautical word describing heavy material added to a vessel to
enhance the available tractive effort. The additional weight increases the
friction between the tires and the road surface. The tractor would be able to
overcome the inertia and friction of rolling the heavy trailed load and its
wheels would rotate without generating forward motion. For example, in the case
of a ballast tractor the weight of a transformer or any heavy load is supported
separately and its weight provides no ballast: the draw bar only transfers a
horizontal force to the transformer.
To overcome the
high inertia encountered the ballast tractor veer to have a high power engines
and engines which provides a lot of torque or moment of force. Heavy duty hub
reduction axles or high reductive gear boxes are usually built-in in ballast
tractors to add torque at the wheel. So heavy duty ballast tractors have low
maximum speeds. A strong chassis is needed in order to support the extra weight
of the ballast and the pulling forces imposed by the draw bar. A reinforced
chassis lets multiple tractors to be joined together to add the total power and
traction accessible. A ballast tractor is the heaviest class of on-highway
trucks.
Transformer Hauling and other heavy and nonstandard loads using independent draw bar
trailer or modular wheel-trailer units is the purpose of ballast tractors.
Another specialized use for ballast tractors is in showman vehicles. The weight
of the showman’s vehicles tends to be much less than those used for heavy
haulage to comply with vehicle weight legislation especially axle loads. There
are times one or more generator sets for powering rides can act as the ballast.
More generators are smaller and can fit between the cab and the fifth wheel of
a conventional tractor unit lessening the need for fairground use of ballast
tractors. Example of a showman’s diesel road locomotive is a vehicle used for
towing fairground rides. A ballast tractor is slightly limited in its use in
modern day road freight because the tractor-trailer combinations are more
adaptable and practical to haul normal heavy loads.
A heavy duty tractor unit
is furnished with a ballast box temporarily which may be utilized as a normal
fifth wheel based tractor unit however its kerb weight is usually high thereby
lessening the payload of the entire vehicle. Most heavy haulage and heavy
lifting engineering firms use heavy duty tractor-unit models which can contain
a ballast box. A large number of ballast
tractors are normally used in countries where modernization takes place because
of the greater occurrence of hauling transformers and other heavy loads. Today
pure ballast tractors are not as popular as before because of the increasing
versatility of self-propelled modular transporter and low loaders. Ultra heavy
loads of 200 tons plus, usually are only transported in short distances and
self-propelled modular transporter are more maneuverable.
