Version 49933 is the last version of Trainz Simulator 2010 that was released. I'm not sure if you have that version or if you have an earlier build and are looking for that patch. If the latter is the case, you won't be able to apply a patch without registering your serial number under your MyTrainz account. See the link above.
You can still buy TS12 on the Steam Platform for a low price. Otherwise, you can purchase TANE or TRS19 directly from N3V or through Steam. Monthly subscriptions are available for TRS19 Plus as well. Just see the link above for the Trainz store.
William