I've visited the Nene Valley Railway at Peterborough a few times, but on each visit the railway wasn't running any trains as it was mid-week and off-season.
However, I won't be constructing a route based upon it on TS12 any time as I shall be concentrated once more on the former March - Wisbech branch once I sort out my computer. I lost my entire (saved) work-in-progress ((based upon the closed railway line to my home town)) when my PC went funny with malware earlier last month.
* Since getting another local railway book on the former 1883 - 1966 GER Wisbech & Upwell roadside tramway, I'm seriously considering of also building this unique little railway.
Andy.