Operating Era: 1910-1970. Baltimore & Ohio. B&O ordered 4,000 early quad hoppers patterned after the PRR H21 in 1910-11. They had 3 different door lock styles, depending on the car builder. In 1922-23 the cars were rebuilt with ladders on the sides and ends. In the mid-1930`s all cars were given Wine door locks. Unlike the Pennsy cars, most W-1s retained their clamshell hoppers until scrapping. Our kit models the car as rebuilt in 1922 through scrapping with 3 door lock sets. The lettering changed 4 times during this period and our decals cover them all.