i installed it and i only have the minecart, how do i fix it?

your depot rail (yellow) must be longer than 12 meters.or there will only spawn minecart .to like reallife,please make it 152 meters long.

Please make sure your siding is long enough to fit a train carriage
You can refer to the Wiki for the length required for each train to spawn.

version 1.20

How long is your Siding? If it is Less than 11 Meters (Blocks), Only Minecarts Spawn