In about 1932, through to the 1950s, the Big Four Railway companies each provided chasses to carry milk tanks for the various Dairy companies. This was continued by British Railways with a standardised design and for whom the customer became the Milk Marketing Board. There were variations within each of the railway companies, particularly in terms of the access ladders and the platforms on top.
The popular Hornby wagon, is distinctive in having no straps around the tank. But these were a very noticeable feature of all the tankers, although some companies were consistent in the platform designs, others had a variety. I hope that we can cover a number of the more popular designs, starting with the Southern Railway. Although the various Dairies used stainless steel and glass lined tanks. These were of the same external dimensions, but there was a variety of valves on the top, apart from the main manhole. Some tanks were initially provided with a sheet steel cover which was intended to provide cooling via the bell-mouthed ends. However these were short lived, presumably because of the effect of spilt milk and the difficulty in cleaning between the tank and the cover, so it is not intended to provide these.
Further details including the positions of the straps may be obtained from the various company reference books, However it should be noted that some authors treat these as goods wagons, such as Russell, and Atkins,Beard and Tourret (GWR) as goods vehicles; others such as Tatlow Historic Carriage Drawings ; Essery (LMS) and King (Southern) deal with them as non-passenger coaching stock.
To apply:- The brackets were intended to be folded back on them selves, so providing a double thickness. However experience has shown that using only half of each etch is easier and more appropriate when putting them into solid plastic. Drill four holes (0.8-1.0mm) into each side of the solebar just below the level of the top flange. then slip the bracket onto the end of the strap and place in the hole. Using some sticky tape hold the strap aginst the tank, and position the other bracket ito the solebar on the other side. Bend the strap over the tank loosely and insert it into the second bracket. Holding the strap on each side of the tank smear some superglue under the top of the strap and move it down to tighten it over the tank. Check while you are douing thi that the strap is square to the tank. After a long 10 seconds, add further supeglue to the backets on one side, letting it run around the end of the strap and into the fixinhg hole. Then repeat on the other side. You may find a better way of doing this, but remember you only have two sets of fingers, and they are of little use when stuck to the model.