Correct properties for cargo wagons
They still need to be completely sorted out. I think there is room for some additional wagons, but which ones? There is very little documentation on Dutch freight wagons. Also I would like to match real life speed limits, capacities, weights etc. where possible. Just like the rest of the set essentially. I think that's plausible for about 20% of the wagons, the rest should be guesstimated to fit in and make somewhat sense.
I've been researching A LOT, looking for more freight wagons but all I can come up with are basically wagons that come into Holland from other countries, i.e. France, Benelux, Germany etc.
As for their max speeds, it should be simple. Consult their UIC codes, IIRC, there is one of the letters that represents their max allowed speed.
Found some UIC codes for modern wagons:
"s" - Permitted in trains up to 100 km/h
"ss" - Permitted in trains up to 120 km/h