Editing Locomotive frame (section)

===Plate frames===
These used steel plates about {{convert|1|-|2|in|1|abbr=on}} thick. They were mainly used in Britain and continental Europe. On most locomotives, the frames would be situated within the driving wheels ("inside frames"), but some classes of an early steam locomotive and diesel [[switcher|shunters]] were constructed with "outside frames".
Some early designs were '''double framed''' where the frame consisted of plates both inside and outside the driving wheels. Others were ''sandwich frames'' where the frame was constructed of wood sandwiched between two metal plates.