Sample ScheduledExecutorService

Dispatcher.java

// create a new thread pool service with 6 threads
ScheduledExecutorService service = Executors.newScheduledThreadPool(6);

// iterate over your list of trains
for (Train train : trainList) {
    // determine how long of a delay between the current station and the next
    int delay = ...;
    
    // schedule the future service
    ScheduledFuture future = service.schedule(new DispatchTask(train), delay, TimeUnit.SECONDS);
}


// alternatively, for a single train (since they'll finish separately):
public void scheduleNextRun(Train train) {
    // determine how long of a delay between the current station and the next
    int delay = ...;
    
    // schedule the future service
    this.service.schedule(new DispatchTask(train), delay, TimeUnit.SECONDS);
}