Tram-Train Future?

Call it what you will. Many do. But the Class 139 RailCar (to give it its correct title) or "Parry People Mover" (affectionately named after its creator John Parry) is proving to be a huge success on the Stourbridge branch line.
Quirky it may seem to some, and often mocked by railway enthusiasts who should know better, "The Parry" has quickly settled down to prove a competent solution to a cheap, environmentally-effective operation for the short branch line in the town.
It operates on a 10 minute frequency for most of the day and meets similarly timed trains on the mainline into Birmingham. No need for a timetable, a transport success story.
I'm sure that rail buffs will attempt to pick me up on the finer points of the Parry operation, but as a mere passenger who uses it regularly, I can only sing its praises from the rooftops. The fact that its technology was developed locally in Cradley Heath is something else us locals can be proud of. The staff too are dedicated to the operation and can be commended.
I've interviewed John Parry on my radio show several times. A colourful character indeed! He's looking to take the project to other areas where the small railcar might be able to provide a similar service.
One such idea is to use a new version of the "Parry" on a local service from Stourbridge up towards Merry Hill and beyond. Many of us are waiting for the day when the Midland Metro tram finally makes it to Merry Hill, and, blue-faced, we're still holding our breath!
Frustrating as it is that us Brits don't "do" tram networks like the French and Germans do, why not mix a small bit of freight and a Parry "tram-train" on a lightly-used currently freight-only section of line?
Yes, the new version would have to be bigger, and the "bounciness" of the current operation needs to be addressed, but it's such an opportunity to put public transport into peoples psyche and create a new link at what in railway terms is fairly minimal cost. I've also never really understood why such a railcar couldn't have been trialled on part of the Severn Valley line from Bewdley into Kidderminster as a commuter link either.
It might not be a "train" or "loco" in some people's eyes, but it's public transport. And the more decent public transport we can get, the better!