The improvements in the TS09 Surveyor were welcomed by the route builders while the different and tighter data model testing and vetting of new assets gave the objects content creators a benchmark to hone their talents and practices. The TS2009 release vetted the 'base content' of the preceding big sellers, and TS10's release had all the new content and new routes, plus the older content.
The two versions share some of the same trainz-build values, so overlap technologically speaking-both have a SP4 which makes both TB V3.3 on the high end, but the TS10 TB's did not always increment with a new SP patch.
The short story on that was TS2009 was a transition step to TS2010 which presented more development problems than anticipated, so was about a year late. The trainz-build (TB) has increase uniformly and monotonically except for the intermingled Trainz TS2009–TS2010service packs (SP) when the product was transitioning from 32 bit computers to harnessing the power of quad-core microprocessors and 64 bit architectures.
