P318 are outer coupled wheels, P319 are mid coupled wheels, P320 are the driven wheels.

1400 mm, 4′ 7″ diam., 15 oval spokes.
Hub of P318, 318 14″ face dia, P320 16½″ face dia., ¾″ below the tyre. Pin at 13″

Casting: 43.8 mm tread dia., 37.0 mm i/d., hub 0.4 mm below the tyre. Pin at 10.3 mm.

Casting prices and stock . Germany loco sets, price list

Scan of castings in a set for a German 2-10-0 Class 52