The Power Bridge is clipping both buildings and vehicles.
powerbridge_clipping.png
Best I could do is remove it...
a bridge always cuts off the stuff underneath it. This is done so for normal bridges, you won't get a tree growing through the bridge or something like that, and it works since the bridge is solid. Clearly, with a bridge that has so little substance, it becomes much more noticable.
But following vehicles in underground mode doesn't clip?
Oh, OK. I see the difference.
oldie
There is another bug report on the forum from me even. This is somewhere is the directional clipping code (it will disappear under fast forward). But that code is so complex that I have given up. It is less visible with normal bridges, but exists there too.
See here https://forum.simutrans.com/index.php/topic,23462.0.html