TrainzMap is a Free utility created by VistaMare to facilitate and enhance route building in TRS2006, TRS2004 and UTC. In particular, it has the ability to render a map of your layout's track plan, complete with as much data about it as you desire, like station names, track marks, signals, etc.
One other very useful feature of TrainzMap is the ability to change many of the objects(assets) in your layout for another of the same kind,(Similar to TrainzObjects)*. For instance, if you decide that you want to change all the point motors on your layout to another type, it just takes a few clicks of the mouse and you're done. Very handy.
You can get TrainzMap here; http://www.vistamaresoft.com TrainzMap is not available for Trainz Classics(TC), however, if you have TRS2006, you can import a route from TC, do your Trainzmap stuff and export it back to TC very easily.
*TrainzMap will exchange any "nameable" asset for another of its kind. (they show up as asterisks when the nameable button is selected)
Items such as trees don't qualify as 'nameable' so you will not be able to do a universal exchange of trees or other non nameable objects in Trainzmap.
If you have TRS2004 and TrainzObjects, you can copy over your route into the '04 world/custom folder, open TO and do the exchange. Create a .cdp file of the revised map and import into '06. It will replace your old version. (Delete '04 copy)