How many decades had passed from the construction of the railway to the construction of the highway in Yucatan?
return the  construction  of the   railway ;return the  construction  of the   highway in  Yucatan ;return when  was  #1 ;return when  was  #2 ;return difference of #4 and  #3 in  decades
['select', 'select', 'project', 'project', 'arithmetic']