I am new to the industry having only passsed my Class 1 in Feb. I have a full time office job in the week but do occasional Agency work at the weekend.
I did a shunting job last week which was good for reversing and coupling and un-coupling. I was lucky because there were no bridges to go under.
My question is - you get in a tractive unit with no height showing and you couple up a trailor. I presume there is a height lable on the trailer headboard, is that for the height at the rear axle. If so when you couple up the tractive unit it may have the suspension high or low so even if you have the height of the cab that could have changed. Is there a fool proof way to work out the overall height. I dont want my first long haul to go with a bang, if you know what I mean. 
Get a measuring tape always carry one if not sure ask never assume nothing .
Height of trailer will be marked on the headboard usually in big bold lettering. It will (usually) also state that it’s that height with a 5th wheel height of 1.25m.
You can get a tape measure or a height stick (telescopic plastic stick) with a 90degree angle and measurements marked from top to bottom.
TJ82:
Height of trailer will be marked on the headboard usually in big bold lettering. It will (usually) also state that it’s that height with a 5th wheel height of 1.25m.You can get a tape measure or a height stick (telescopic plastic stick) with a 90degree angle and measurements marked from top to bottom.
If you’re lucky. A lot don’t.
James the cat:
TJ82:
Height of trailer will be marked on the headboard usually in big bold lettering. It will (usually) also state that it’s that height with a 5th wheel height of 1.25m.You can get a tape measure or a height stick (telescopic plastic stick) with a 90degree angle and measurements marked from top to bottom.
If you’re lucky. A lot don’t.
I forgot that bit
Thanks for the tips. Seems like a large tape measure is in order. 
Most of our trailers show height based on a 1250mm 5th wheel, but the odd one has it based on a 1320mm 5th wheel.
The weird thing is that all the units run at 1320mm, so for most trailers there is an extra 70mm to add on to the stated trailer height (just under 3 inches).
Furthermore, don’t forget the running height of your wind deflector. We have some trailers at 13’ 1", plus the extra 3" on the 5th wheel makes 13’ 4" right? Wrong, the wind deflector on the cab runs at 13’ 6" so that is the height I use to set the height marker inside the cab…never less than 13’ 6".
ORC:
Most of our trailers show height based on a 1250mm 5th wheel, but the odd one has it based on a 1320mm 5th wheel.The weird thing is that all the units run at 1320mm, so for most trailers there is an extra 70mm to add on to the stated trailer height (just under 3 inches).
Furthermore, don’t forget the running height of your wind deflector. We have some trailers at 13’ 1", plus the extra 3" on the 5th wheel makes 13’ 4" right? Wrong, the wind deflector on the cab runs at 13’ 6" so that is the height I use to set the height marker inside the cab…never less than 13’ 6".
Do you ever wish you had paid more attention in Maths class.!!!
Many thanks for the advice. I look forward to the challenges.
P.S. B&Q 8mtr tape measure now in my travel bag