What should transports use?

You gotta check some tings, and try to be more precise with your postings. You post things directing to different INI files.

Make sure you have :
[EncounterParameters]
nickname = area_trade_transport
filename = missions\encounters\area_trade_transport.ini

in your system file.

Next check your faction_prop.ini if indeed
npc_ship = co_alg_ge_large_transport_d5 is added to your faction.
Also check if:
formation = transports, transport_kusari (where kusari can be rheinland as well)
is in this file.
Also make sure you have a fighter entry in this file, because the encounters have fighters in it as well.
npc_ship = co_alg_ge_fighter2_d5
formation = fighters, fighter_basic

Go back to your system file if you have this to the zone you want it.
encounter = area_trade_transport, 1, 1.000000
faction = your_faction_name, 1.000000

This basicly means that only this faction can exsist at this zone, if you add more encounters devide the 1.00000 between those, and a higher number per faction makes it more likely to have that faction come on earlier.

Well, to help you out a bit more info would be useful as you didn’t mention which faction you want to appear. It would help checking out your code then.

So far I can say, check if the transport you want to appear is defined as “class_transport” in the npcships.ini then see if you have a “class_fighter” defined ship at level 5 AND a “class_fighter” defined ship at level 4 as both are needed for this encounter to appear.

If one of those ships is missing, the whole encounter won’t work.