The first self-propelled modular trailers17 July 2007
In your article "Modular transporters for modular construction" (April 2007 pp 69-73), you say that the first self-propelled modular trailers were developed by Econofreight in the mid-1980s.
This is false. The first SPMTs were developed by Mammoet in conjunction with Scheuerle in Pfedelbach, Germany. The two started developing SPMTs in 1983 and put them to use in 1984. Econofreight only purchased Nicolas SPMTs years later.
There were already self-propelled trailers in the market but Mammoet designed these in such a way that they were easier to assemble, and, more importantly, a lot more economical.
Our SPMT designs with a width of 2.43m wide and 5.6m long (four lines) and 8.4m long (six lines) were a world first. They enabled the SPMTs to be transported on standard 20 and 40 ft container flatracks. This was a big development in comparison with the earlier axle lines that had a minimum width of 3m. Also these were the first with the 360° steering capabilities.
The main reason why they were developed was that the oil and gas industry was moving to much higher weights in offshore production platform modules. The smaller dimension of trailers was beneficial for mobilization but also allowed more lines to be fitted under the modules.
-Jan Smout, ?Regional Operations Manager, Mammoet Middle East