There are two types of bogie. The older type is fitted (permanently) to the chassis by a brass tube rivet. The newer type is fitted with a plastic spring clip, so the bogie can be easily removed and refitted. I'm looking to refit the older type bogies using a (brass) bolt and nut. Do any of you have experience of (re)fitting bogies this way? There is a plethora of bolts and nuts available. How do I determine, with confidence, the sizes/types I need? I look forward to any constructive suggestions, and thank you in advance.