Aspects of the invention include methods and systems for a testing mechanism to be utilized when repairing and replacing a valve utilized on a tank car. The testing mechanism may comprise a pipe plug device configured to plug a siphon pipe located on a tank car and a pressure test device to conduct a leak detect test after the pipe plug device is removed from the siphon pipe. The pipe plug device may include a pipe plug bladder and a pipe plug pressure fitting to inflate and deflate the pipe plug bladder against a wall of the siphon pipe. The pressure test device may include a pressure test valve cap with a test valve bladder located on the pressure test valve cap, a bladder pressure fitting to inflate and deflate the test valve bladder, and a test pressure fitting to pressurize a valve, the test pressure fitting located on the pressure test valve cap.