[FROM: Alexander Pavelek]
Many people keep on asking about the gem trains. It is a bit complicated so I will try explaining how it works. It may not be completely exact but the important things are there:
You can receive a Gem Train every 23 hours. Every time You do log into the game (after the 23 hours from the last Gem Train You received), the trigger to send You a Gem Train will start. It will generate a random number between 1 and 60 minutes - this minutes represent the time in which The Gem Train will be send to Your station. After sending the train will last in Your station for 1 hour, just as a normal NPC train. Generally this means that You might not be right at the 1 hour time at Your PC and the Gem Train leaves.
To make it more clear hers an example:
The trigger is set on 22. You login into the game at 23. The trigger starts. In 30 (I just randomed the number) minutes the train should arrive at Your station. But meanwhile You turn of the pc and go sleep. The Gem train will come at 23 and at 0 leave Your station. Unfortunately You wont be able to catch it. The next day it wont come again the whole day, until the 23 mark. - This is just an example, but the problem might be something like this.
We know that the Gem Trains are not transparent, we are trying to update it so it will be more easier to track Your Gem Trains, hopefully we can make it as soon as possible.