The designer of the Euroreprap Railroad Collection, Instructables member MWPLUS, shared the project and included extensive pdfs with instructions for assembling each of the components, from tracks and a semaphore (the signal), to locomotives and carriages. The inspiration for the collection and for its individual pieces was, explained its maker, inspired by his/her children.
In that spirit, this seems like an ideal project for a family of makers and model train enthusiasts. The objects in the collection are superbly designed, evidently not difficult to assemble, and, better still, can all be 3D printed even on small home 3D printers. No support is needed, no metal parts are included, and you need only a minimal toolset to complete assembly, which is pretty fantastic.
Right now, the collection is a bit limited, but new objects are being released incrementally–also inspired, we imagine, by the designer’s children. While the individual 3D printed objects shown were printed in a single color–an off-white shade–one photo shows the maker’s child holding a blue locomotive, so it isn’t unreasonable to consider painting your train cars and tracks if you’re going for a more finished and realistic look. The kind of paint you use depends on the material you print them. For instance, according to the folks at MakerBot, you can use cellulose spray paints or oil paints with PLA, but water-based acrylic paints are best for that material. Also, you will likely want to use a non-toxic paint for the train set if it is for your kids.
As for other tools and materials you will need to complete this project, expect to do some minor sanding and clean-up and note that you will be using glue, so be sure to work in a ventilated space and give your small assistants age-appropriate tasks.
Even if you aren’t up for this particular project, be sure to take a look at the pdfs provided by the designer as they are beautifully designed and illustrated. Once you’ve seen them, however, we can’t imagine you won’t be fully on board and, well, full steam ahead.