from what I could find, that is a 2 ton unit.
this is from a FAQ on Trane's website:
How do I verify the size of my air conditioner or heat pump?The capacity in tons of a Trane outdoor unit can be determined by dividing the 7th and 8th digit of the model number by 12. So if the model number is 4TTX4036A1000A, take 36 and divide by 12, equalling 3 tons.
This is only for Trane models. Other companies use a different method based on their model number nomenclature.
yes, I know the 24 in yours is the 6th and 7th digits but if you will notice there is an extra letter in the series before that number in their model nnumber.