Circa 1908-1909: Numbers 0 to 4 had the same basic structure, except for the number and the size of the spring. Note the small rear wheel, smooth boiler and red litho plate. Note the different casting used on these Locomotives from the comparisons below.

Side by side comparison of most of the smaller Locomotives from 1909-1911. Note the one in the middle that has the plate 'The IVES Miniature Railway System'.  It was actually pictured this way in the 1908-09 catalogs - but the couple that we've actually seen were both from approximately 1909-1910.  Note in the photograph below and above when you compare the reverse Bicycle locomotives with the 2-2-0 version they are Identical except for the lenght of the cab. The cab on the 2-2-0s are approximately 1/2 " longer.