If you don't want to use RW_Tools, here is a free solution:
Rail Simulator - RS Misc.
KRS Bin Convert Update
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Name: krsbc115.zip Size: 432,659 Date: 04-16-2008 Downloads: 914
KRS Bin Convert Update, v1 build 115. Update to the KRS Bin Convert program, including bug fixes. .dds header problem finally resolved, image info-prompt added, open file capability added, plus other enhancements, now compatible with Mike Simpson's tools. Full Install. By Bill Scott.
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I pair it with a free copy of Context (
http://www.contexteditor.org/downloads/)
I use RW_Tools for many of its features, but prefer to edit RW files (bin, GeoPcDx, lua, etc) using the combination of KRS Bin Convert and Context (and they are free)