D37 These are very! very! early prewar Marklin 3 rail track.  there are 15 -72" curved and 23 straight track     they measure 1-7/16" out to out on the rails. Not quite the 1/2", it has to be mm being German? But a Lionel car did fit wheel wheels. Selling as is shown with no returns on used items. Thank You for looking will combine on S/H, shipping UPS