Tugger trains are means of transport used in intralogistics processes, primarily in manufacturing companies.

Other common terms are logistics trains or tugger train systems. Like other industrial trucks, they are used for the in-house transportation of production equipment, where they bring inventory, materials, finished and semi-finished products from the warehouse to the production or assembly site on horizontal levels, usually just-in-time, and from there transport them onwards.

In contrast to forklift trucks, for example, they can transport several load carriers per journey and are the safest solution for comparable intralogistics material flows due to their fixed routes.

Structure of tugger trains

Tugger trains consist of a towing vehicle, the goods carriers and load carriers. The towing vehicle is usually a converted electric tractor, which acts as a kind of locomotive. The individual goods carriers thus form the counterpart to the wagons of a train, while the load carriers contain the transported goods and are used to load the goods carriers.

There are different systems of goods carriers that differ in terms of the type of loading (floor-level/non-floor-level) and loading direction (one-sided/both-sided). The design of the load carriers depends on the respective application and is very individual. Often, certain load carriers are already in use in a company, whereupon the goods carriers are then adapted accordingly.

Examples of goods carriers and load carriers

How tugger trains/tugger train systems work

The load carriers are used by the tugger train to pick up the transported goods at the source (warehouse, assembly site) and transport them to the sink (unloading point). New goods or empties can then also be loaded there and transported onwards. In this way, several drops can be accessed on the route in the course of one journey. In contrast to transportation by forklift truck, this saves unnecessary distances, which significantly reduces the volume of traffic in the plant. The activities to be performed, such as driving, loading and unloading, can be carried out manually by employees or they can be partially or even fully automated.

Tugger trains versus forklift trucks

Tugger trains are now being used more and more frequently, replacing forklift trucks as industrial trucks or means of transport. Forklift truck accidents still occur frequently and often have serious consequences, both financially for the company and for the health of the workforce. These health and economic damages are greatly reduced by the introduction of tugger trains, which create a much safer working environment.

In addition, forklift trucks incur higher costs, both in terms of purchase, maintenance and operation, for which a separate driving license is required. The advantages of tugger trains over forklifts include:

• The reduction of operational accidents
• Lower energy consumption
• Saving time by transporting several goods carriers and load carriers at once
• Easier handling
• Lower operating costs
• Individual adaptation of the goods carriers and load carriers to the transported goods
• The possibility of automation

The comprehensive introduction of a tugger train system can be seen as a disadvantage, which may require far-reaching changes to internal processes and infrastructures.

Automation for tugger trains

Tugger trains can be fully or partially automated. Automation can therefore affect individual processes or the entire tugger train system. If the tugger train is automated, this can be done using magnetic tapes, magnetic points or RFID, geonavigation or even color ribbons. For this purpose, the towing vehicle, i.e. the tractor, is equipped with the appropriate technology, which also enables mixed navigation using the aforementioned methods. Semi-automated driving can also be implemented, in which individual actions run automatically, similar to the independent parking of a car.

Loading and unloading can also be automated. Load transfer can take place using roller conveyors, extendable telescopic forks or automated underride AGVs.

Summary

Tugger trains are industrial trucks used for the internal transportation of inventories, materials and other goods. They consist of a towing vehicle, goods carriers and load carriers. They are generally used in production or assembly, but are also used elsewhere, for example for waste disposal in companies or amusement parks, but also as a means of transportation at airports, in the catering industry and in the pharmaceutical and food industries. Due to their various advantages over forklift trucks for internal transportation, they are increasingly replacing them and are an indispensable part of a (fully) automated factory.