I got inspired by similar designs on the web, but they were too bulky and often even needed support.
I designed this here fully from scratch, since the original (and any others I saw) seemed to be quite excessive on material use and not fully compatible with all rails around.
Here are the improvements in my design: less material (about 50% only) and faster print (almost twice as fast) with same functionality based on 2×2 Duplo brick instead of 2×4 reduced rail depth to 2.5mm (instead of 3mm), which improves wheel traction significantly (long story and many experiments, but it seems to work better) I even experimented with using a single Duplo buildplate and made 2 versions to allow an even distance bridging matching Duplo standards: Short: Most minimalist design, but cannot bridge 2 columns fixed on a single Duplo build plate (½ pin too short) Not-short: Half a Duplo pin longer, so can bridge 2 columns on a single plate (of course that can still depend on the brand and length of straight connector you use, but one of the 2 versions should work either way Disclaimer:
