I am Alstom customer. How to download this Romon2 commissioning tools and VNC Viewer?
You have to contact the developers of the application because there is no public way to download the software to your PC. The VNC Viewer is available separately on its official website, but can't say the same for ROMON2.
Access the following link in order to contact the developers: http://www.alstom.com/contact/