i know in the case of SPAR, they could drop the trailer, run around in the wagon for shop deliveries and then transfer the loads between the wagon and trailer. the kind of used it as a mobile warehouse for the shop deliveries
Here in Finland we use rigid and drag mostly becouse historical reasons. When longer combinations are allowed there was already big numbers of similar but shorter combinations. Logical step was to get longer trailers. Driving at winter is also considered big disadvantage against normal artics or 25.25m long artic + mid-axle configurations.
As Scanny77 said trailers are used also as a mobile warehouse when delivering or you can have different temperatures in rigid and trailer boxes for example when carrying perishable goods. You can also deliver to places where you couldn’t even imagine going with artic. Generally wagon&drag is more flexible than artic.
Artics have usually trailer lenght something near 13.6m. Wagon and drag can have 15.65m long box total with maximum lenght limited to 18.75m. So cubic capasity is little higher. In Finland and Sweden we have maximum cargo space limited to 21.42m with total length limited to 25.25m. Max lenght of rigid is limited to 12m including cab.
In a lot of Western Europe, there is a maximum height of 4 metres (13’3"). So to get the maximum cubage a lot of companies run on low profile tyres which will give you a volume of 100cubic metres at our maximum artic length (17.5m bumper to bumper). Wagon and drags have a longer maximum length of 18.5m. The trailer can be on smaller wheels as well, which gives a volume of about 120 cubic metres. The extra length allows some extra pallets as well.
There are some fancy setups with the A-frames as well, to give even more load space. These A-frames have a hydralic ram in them and a sensor setup fitted to the front of the trailer. In a straight line, they run with a gap of 3 - 4 inches between the wagon and trailer. When they bend, when going round a corner, the sensor lengthens the A-frame to stop the wagon and trailer binding together. That can increase the volume and allow yet another row of pallets. I would expect these rigs to be heavier though,so they will be a bit restricted in payload.
My artic is a little heavy. I run a three axle rig with a lifting second steer. So the lifting gear and the steering gear make it a bit heavier, and the third axle probably weighs about 1.5 tonnes, which, with full tanks means I weigh 16.5 tonnes with an empty trailer (our trailers are pretty old as well). With the UK max gross being 44 tonnes, I can carry 27.5 tonnes. The European max is 40 t, which knocks me back to 23.5 t loads. The loads we bring back from Europe usually cube out before they weigh out.
I did once see a company in Utah that used a “W&D&D” setup (3 axle truck pulling 2 trailer on a-bars) for delivering fuel oil. They would drop the trailers, go make a delivery, come back, drain the kite trailer into the truck, go make a delivery, come back, drain the lead trailer into the truck, go make a delivery, come back, hook up, and head down the mountaind to Salt Lake City.
It is all about flexibility Alex, Alot of our W&D have demountable bodies, this means that the boxes can be dropped at a satelite depot and the contents can be deliverd by a smaller truck (typically 7.5t) to residential areas. This is popular with home delivery companies over here.
At Toray we had wagons & drags with interchangeable demount boxes, so for tight deliveries we could swop them over.
Method was to drop both boxes in a straight line then drive forward pulling the trailer under (what was) the front box. Remount it then pull out of the way, drop the trailer and go back to put the other box on the wagon. Re-couple and off you go. Sounds a bit of a do but it enabled us to do multi-drop restricted access deliveries outward bound and then backload with bulk intake for the factory.
It cut the delivery fleet in half and did away completely with artics running halfway empty for bulk loads. A big saving.
Salut, David.
Liberace:
Been offered a training course on one, but am wondering how “different” they are to an artic to drive. If I say yes, this should be “interesting.”
Going back to the original post, is it a ‘freebie’? If so, why would you ever think of not doing it■■?
Gimmie freebies!!! 