I doubt very seriously if you'll be able to find any replacement parts. Herein comes one of the fun parts of scale modeling - just make them yourself. It's not rocket science. If you've never scratch built anything, here's a great opportunity to do so, and it's not a particularly daunting task, either. The handrails can be constructed out of .015 brass wire, the stanchions can be cut from strips of polystyrene, and the chain is ready-made in various sizes/lengths - all available online or through your local hobby shop (if you're fortunate to have one close by). There are several tutorials on YouTube that can help guide you. All you'll need are a few tools for the miniature hobbyist - wire cutters, needle nose or thin, flat blade pliers for bending, and a pin vise with various little drill bits. Plus, the real satisfaction comes from knowing you built them yourself! Once you start, it opens up a whole new world for detailing and adding missing bits or pieces to your engines, rolling stock, or accessories. Just don't be afraid to try. You'll find it'll be well-worth your efforts in the long run.