Two-wheeled carts attached to the horse
This would be interesting too, because here you can add wheel failures or broken attachments or even crashes/touches with the other two-wheeled carts on the track. It would also somehow complete the game with all (basic) racing versions and would be easy to integrate. In the end, you can use the same tracks, but without jumps/fences, and it would need just an additional failure column(s) in the RUN table, to add some more spice and variations to the race.
Broken/ripped of reins
This would end in a kind of "out of control" value, that can be fixed - so depending on the dice value, you lose speed and have a high percentage of hitting other ones on the same furlong position or - worst case - you're out of game.
In this case you will lose speed for the rest of the race or drop out completely.
Touching/Collisions between two carts
This will be interesting to implement - maybe I will connect it with the RUN dice result and the position of two horses. So if both horses for example are on field 14 and have the same main split time, then you have to roll the dices for the collision possibility. Here we will use the same dice result share - middle values you are okay, otherwise you will collide. If this happens, then you have to roll again and check the fall table (or there is a connect to the broken wheel result).
Upcoming / in progress