Have you seen self-propelled modular transporters (SPMTs) at work and wondered how they function? The capacity of these heavy haulers triggers the curiosity of many people.

SPMTs have the capacity to carry the heaviest cargo in the world. You will find them at work in construction plants and shipyards. In this article, you will discover the reasons why the haulers are widely used in the industries.

SPMTs have different designs and structures. The structures differ depending on the model and final use of the SPMTs. This article outlines all the major features of SPMTs and their PPUs.

You will also learn the difference between mechanical steering and electronic steering systems. The article goes further to explain why sometimes equipment falls off from SPMTs while in transit.

Who are the top manufacturers of SPMTs? The article discusses the top SPMTs in the world.

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  • Basic information you must know about SPMT

There are different claims about the company that developed the first self-propelled modular transporter. At first, it was thought that Econofreight was the first company to introduce the heavy haulers in the market.

The company introduced its first model in the mid 1980s. It claimed to have manufactured the first SPMT with a German company called Scheuerle.

scheuerle modular trailer

The first designs had a width of 2.43m and length of 5.6m for four axle lines. Those with six axle lines had a length of 8.4m. 

SPMTs have evolved over time because of the need to fabricated equipment offshore. Before the SPMTs were introduced, engineers would fabricate all equipment on site.

The greatest limitation of the development heavy equipment on site is the lack of infrastructure. Today, modular transporters have enabled engineers to overcome this and other limitations.

They can develop equipment offshore and overcome limitations of time and space. The modular transporters are then used to ship heavy equipment from the construction site to the final destination.

  • Why SPMTs are widely used in shipbuilding and construction

If you want to see SPMTs in use, then you should visit shipyards and construction plants. The coupled transporters have a loading capacity of about 10,000 tons.

SPMTs have the highest loading capacities in the world. For this reason, engineers use them to transport bridge sections and large ships.

Bridge modular trailer

The heavy haulers can be coupled together to increase their capacity. Hence, they can transport wide and long construction equipment. Another reason why SPMTs are widely used in construction plants is that they enable builders to increase their efficiency.

The speed of transporting construction materials and equipment is greatly increased with modular transporters. In the past, it would take several months to replace an old bridge.

This is because all the concrete components would be fabricated on site. Highways would be closed for months until the bridge sections were completed and installed.

Today, concrete components are fabricated off-site and transported to the site. It takes only 22 minutes to replace a whole bridge section. SPMTs have enabled construction plants to reduce their downtimes.

The transporters provide a way of lifting, carrying, and installing modular constructions. State governments benefit from SPMTs when constructing bridges and roads because they are able to control the construction environment.

Another reason why SPMTs are popular is that they enable construction companies to reduce overall costs. When ships and concrete components are fabricated off site, constructors are able to save on the materials.

anster modular trailer

Hence, the overall cost of construction projects is reduced. The projects are completed faster and at a reduced cost. The construction teams can allocate enough time for curing concrete components.

Some construction projects like bridge replacement leave wreckage on the site. SPMTs provide a way of removing the wreckage. In addition, the modular transporters provide an efficient way for decommissioning large installations.

New construction equipment is manufactured every year. Modular transporters provide a way of trading new and second-hand heavy equipment in all parts of the world.

  • The difference between the two major types of SPMTs

Although SPMTs are used to lift, transport, and install the heaviest structures in the world, they come in different types. The capacity, features, and uses vary from one type to another.

There are many ways of categorizing all the SPMTs. The major way that modular transporters are categorized is in their steering systems.

Two major types of steering are used in SPMTs that include mechanical steering and electronic.

A mechanical steering self-propelled trailers has a rated loading capacity of 180 tons and a dead weight of 30 tons.

When the SPMT is empty, it can move at a 10 km/h. When it is fully loaded, it travels at 5km/h. The low speed is expected because of the heavy loads that they carry.

Its axles have a turning radius of ±55 degrees. The SPMT has four braking axles and a traction force of 640KN. The transporter is about 13000mm long while its platform is 9000mm. Hence, any load within the 9000mm length can be carried with the SPMT.

drive axle

Its lowest height is 875mm. These dimensions are very important when you are looking for a self propelled trailer for your business.

You must consider the average height and length of your regular freight to pick the right modular transporter. The wheelbase is 1500mm and the tread 1800mm. The total lifting stroke for the SPMT is 600mm.

Electronic steering SPMT (Self-propelled modular trailers) have different dimensions, features, and capacities. This kind of SPMT is a large platform with dozens of wheels beneath.

It is different from as mechanical steering trailers in that it has an electronic multi-way steering system. The SPMTs have different bolt-joint combinations. Some have lateral and longitudinal mechanical bolt joint combinations.

Others have electronic combination modes with no bolt joint. The SPMT has a turning radius of +130 degrees or -100 degrees. The rated load capacity is 216 tons while the deadweight is 30 tons.

The SPMTs have 6 axle lines, 4 drive axles and 8 braking axles. Their grade ability at full load is 7% while that of mechanical steering trailers ranges from 8.5% up to 20%.

The SPMTs have a total lifting stroke of 600mm, a traction force of 320KN, and a wheel base of 140mm. The full length of the transporter is 12,600mm while the platform is 8400mm long.

electronic steering spmt

From these dimensions, you can tell that the SPMTs can handle longer cargo. The width of the platform is about 2430mm while its lowest height is 1200mm.

The tread of the SPMT is 1450 mm long. The capacities of PPUs in the SPMTs vary. Some have small PPUs of 103kw while large SPMTs have large PPUs of 390kw.

The PPU size depends on the engine in the self propelled modular transporter. The advantage of SPMTs is that several of them can be combined or coupled to transport large and heavy construction components.

The normal transport capacity of the SPMTs ranges from 90 tons to above 16,000 tons. Some of the massive objects that the SPMTs transport include bridge sections, huge vehicles, and oil refinery equipment.

  • Features and structures of SPMTs

The specifications of SPMTs features are different depending on the manufacturer. Here we will give you the specifications of the best modular transporters in the market.

However, the differences in structures and features are usually minimal. The first important feature in SPMTs is the power pack unit (PPU).

The PPU is the source of power for the electric steering system in SPMT. The PPUs also supplies power to the hydraulic systems that control the braking system and the axle height.

spmt ppu

As indicated earlier, the parameters of PPUs vary depending on the modular transporter. Consider this modular transporter with a load capacity of more than 10,000 feet.

The higher capacity PPU has a liftable angle of 12 degrees and a dead weight of 7,000kg. The fuel tank has a capacity of 400 liters while the hydraulic fuel tank can hold 850 liters.

The voltage of the electrical system that the PPU powers is 28V. The driving systems can withstand a pressure of up to 400. The maximum pressure for the lifting and steering system is 300 bars.

The number of driving axle lines for this modular transporter is 30. This is just one example of a PPU from a specific manufacturer. The parameters of the PPUs are not so different.

For instance, the voltage of electrical system ranges from 24V to 28V for most PPUs. The capacity of fuel tanks is for most of them is 400l while the hydraulic tank can be 800 to 850litres.

The major difference in PPUs is the power capacity. Smaller PPUs range from 132-155kw while larger PPUs large from 350kw- 375kw.

When you are looking for a modular transport, the power capacity should be your main consideration for the PPU. The parameters of modular transporter vary as well.

The size will depend on the number of axles. Remember that SPMTs can be coupled laterally or longitudinally to increase their capacities. The length of modular transporters with 4 axle line ranges from 5600 to 6000mm while the width ranges from 2430 to 3000mm.

spmt drawing

The height ranges from 1300 to 1600mm. The length for 6 axles SPMT platform range from 8400 to 9000. The width and height of the platform are the same as that of 4 axles SPMT.

SPMTs travel at 5 km/h when fully loaded. The wheel distance is about 1800 and the average turning radius is ±110. The average axle distance is about 1500.

The load per axle line ranges from 34 to 36 tons while the load per pendulum axle is between 17 and 18 tons. The total weight for 6-axle modular transporter is between 204 and 216 tons.

A 4-axle modular transporter has a total weight of between 136 and 144 tons. Again, all these parameters will depend on the model of the transporter.

The secret when buying a modular transporter is to pick with the load capacity and the largest platforms. Other important features of SPMT include the lifting stroke that is estimated at 700 ±300mm. The steering mechanism for SPMTs is electronic.

  • Additional details about SPMTs

You now know the basic information and parameters of SPMTs. The information can help you differentiate models of modular transporters. Here are additional interesting facts about SPMTs:

  • Reasons why equipment may fall from SPMT platforms

Trailer stability is important when transporting heavy cargo for various reasons. Stability reduces the risks of accidents, which leads to injuries to people.

Accidents also damage the environment and the equipment or cargo in transit. Accidents create additional costs because projects are delayed. The equipment must be replaced or repaired before it can be used for construction.

Most of the accidents are caused by human error and not mechanical failure. When handlers are not properly trained, they do not load the cargo properly on the trailers.

Each modular transporter has a maximum loading capacity. The manufacturer specifies this loading capacity. Loading SPMT with an equipment or cargo that exceeds this capacity will cause it to topple off the platform.

Another reason is loading equipment that is too tall for the platform. Tall equipment requires a wide surface to stay balanced on the road. Hence, the best way to transport such cargo is couple several SPMTs to accommodate the weight of the equipment.

spmt support

spmt support


underestimating the weight of the equipment will overload a modular transporter. You must have the right weight of the equipment to determine the right transporter to use.

Another reason is the malfunction of the axle suspension system. Each axle line is controlled independently. Hence, the axle line can be raised of lower whenever there is an obstacle on the road.

If the suspension system fails, the axle line will not move up and down as expected. The equipment will topple off if the wheels hit an obstacle instead of climbing over it.

It is important to maintain SPMTs to avoid such failures especially when the modular transporter is fully loaded. The position of the equipment will also affect the balance of the trailer. If the full weight of the equipment is not distributed evenly, the platform will not remain balanced. Electronic failure can also cause the trailer to topple.

  • Top brands of SPMTs

The top manufacturers of SPMTs in the world include:

SCHEUERLE: The Company is part of the Transporter International (TII) Group. The Group is among the leading providers of heavy-duty transporters.

SCHEUERLE has been in the transport business for more than 400 years. It manufactured its first transporter in the 1860s. The company is the largest in the Group and manufactures leading SPMTs.

Its main products include power boosters and compact vehicles used for road transportation. It also sells modular vehicles for road transport, SPTs, and SPMTs.

KAMAG: The manufacturer is also part of the TII Group and has also been in business for more than 400 years. Consequently, the company guarantees its clients of the best SPMTs and other heavy haulers.

The company is based in Ulm Germany and has more than 300 employees. KAMAG deals in SPMTs, special transporters, power booster, vehicles for terminal logistics, and shipyard transporters among others.

goldhofer trailer

GOLDHOFER: It is one of the leading brands in the world. The company joined the transportation industry in 1705. It has distributed its heavy haulers to more 160 countries.

The company specializes in modular trailers, semi-trailers, and airport cargo transporters. GOLDHOFER is popular in the world for high quality products.

COMETTO: The Company started manufacturing heavy-duty vehicles in the 1950s. However, it manufactured its first self-propelled modular transporter in 1981.

Although the company joined an industry with well-established competitors, its products are highly competitive. COMETTO has special transporter of air and space, shipbuilding, oil and gas, and wind energy industries.

ANSTER: The Company is a China-based manufacturer that is dedicated to providing its clients with perfect transport solutions. The company was established in 2000 with aim of reaching the high-class market in its country.

NICOLAS: The manufacturer is one of the top companies that form in TII Group. It started assembling transporters for the agricultural sector in 1855.

nicolas spmt

The Company has been producing industrial transporters since 1939. It stands out among SPMTs because of its massive ship transporters. The transporters were introduced in the market in the 1970s.

  • Other interesting facts about SPMTs

Here are more facts about SPMTs that you probably do not know:

• SPMTs have transformed bridge construction and led to accelerated bridge construction (ABC) methods
• Each axle in SPMT is controlled independently
• SPMTs can drive automatically even without the tractor’s traction
• SPMTs can be customized to fit the client’s transportation needs
• SPMTs move at a walking speed
• A computer or a hand-held device can control the heavy haulers
• Some modular transporters have a driver cabin for control
• A wired or radio remote controller is used to operate SPMTs

  • Conclusion

You can now confidently say that you are an SPMT expert. We have provided all the information you need to know about SPMTs. You can actually help someone to pick the best vehicle for heavy transport. Most people see the modular transporters but have no idea how they came about.

From this article, you learn that SPMTs have evolved since the first was manufactured in the 1980s. The transporters are widely used in the shipbuilding and construction plants. They have a high load capacity to carry the heaviest equipment and construction materials.

Today, construction teams take less than half an hour to replace an old bridge with a new one. The dimensions and parameters of SPMTs vary depending on the model.

The leading manufacturers of SPMT include Scheuerle, Kamag, Goldhofer, ANSTER, Cometto, Nicolas. Hence, you are guaranteed of top quality transporters from the manufacturers.

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