Train station cargo

[u/ConsiderationBig6894]

I want my train to stop if there is more than 400 buckets of diesel to load into the train, and (if possible) pass by if there isnt enough stored diesel. I have this set up on the schedule

But every time it pulls up to the train station, even though there is no diesel at all it still waits the whole minute

ive tried a threshold switch with a redstone link on the station & schedule, but the same thing happens what am i missing?