What is the Encumberance Value?
In each race every horse has to beat every other horse in order to win. That's a rather simple sweeping statement but what does it mean?
To beat every other horse in the race one has to beat the Race Class which is effectively a number describing the race. Not only does the horse have to beat the Race Class but it has to overcome the weight that it's carrying.
So for simplicy the Encumberance Value is the sum of the Race Class and the Weight (in pounds) that the horse has to carry.