This is my Lego scammell 100 tonner. It includes real steering via a wheel above the cab, and has chain drive, much like the real thing. I have also built the 100 ton trailer built specifically for the orginal scammell 100 tonner's of which only two were ever built. You may have noticed that due to lack of bricks, the left headlight doesn't actually have a 'bulb'.
About this creation
This image shows the wheel used to steer. It travels down behind the cab and into the 'fuel tank' where it is then horizontally transferred to the actual steering mechanism through the chassis.