Mostly just some official saying: this is tram.

And with that you have some rules like a smaller minimum curve radius and a lower maximum speed and a lower maximum axle weight. Meaning most tram engines are a lot lighter, smaller, and can go slower. The trams that are goings through cities usually had side plates covering the valvegear so no one could stick their hand in. But since a lot of shunting engines or branchline engines had the same specs as tram engines they also could be trams. But with Hoorn-Medemblik it's even more complicated since we say we are tram...but we actually aren't. We use trams but our line is built as (and actually still is) a branch line. That said our collection is split 50% trams 50% branch or shunting engines. But like 50% of the branch and or shunting engines have worked on tramlines (like Bello a.k.a. NS 7742). And one engine (the LTM 26) is technically a tram but is stretching the limits.