Need your help, Big Thanks in advanced.

I am working with one of my clients to help them to define testing techniques for Railway system. I have to admit I have never worked on railway system application but the company I work for have put on this project to help our client. Can someone here who has experince in such project, help me with this please. looking for following information

* Testing techniques / type of testing
* Environment for testing
* relevant risk that may appear
* any other info

Background: Currently we are in planning phase and writing up Test Plan and documents for a 1st phase for delivering a piece of functionality SII Module.. The system has been around or 25 years and requires an upgrade due to new technology. The application will be able to remove the remaining Deplore Virtual Machine hardware and replaces with proprietary serial based communication network, which should provide reliable and cost effective hardware and industry standard messaging system.

The plan is to develop the system in number of modules which will be treated as an individual applications which then be integrated as a complete system later.


* System has an active channel to SSI

Trigger state:
* Time between request being elapsed

Post condition:

* The state module is updated
* request removed from the list
* Invalid response being removed
* X response is received