The model has a rectangular base; W(model) = 1.5 ft , L(model) = 2 ft.
If the scale is 1 : 150, then the length and the width of the actual railroad building are 150 times larger.
W = 1.5 * 150 = 225 ft
L = 2 * 150 = 300 ft.
Area: A = L * W = 300 * 225 = 67,500 ft²
Answer: the area of the base of the actual railroad building is 67,500 ft².