I've created a model of a manually operated lifting arm barrier for my 7mm/ft scale 1/43 scale O gauge model railway. This type of barrier can be found at security points and car parks all over the place.

The model is printed as 3 separate parts. Holes are preformed to accept a small piece of wire to act as a pivot pin which allows the barrier to be fully poseable in open or closed positions and anywhere in between. I use 0.8mm copper wire. The barrier is an interference fit over the upright so it stays in position. (It could probably be filed back a little to make a looser fit if you wanted to automate it. I haven't tried - yet!)

I have included various barriers representing real world lengths between 3 and 6 metres. The longer barriers have larger counterweights as you would expect.

I sliced the model using Lychee and printed on my Anycubic Photon Mono X printer using Siraya Tech fast white resin.