This is a Morning Sun Books 8568 Covered Hoppers Volume 2 NAHX-XTRX: A Sampling of Privately-Owned Covered Hoppers 1961-1995 (Softcover). All hopper cars must have reporting marks ending in ?X,? and must have been painted in something other than ordinary grey with minimal stenciling. Plainly painted cars in any other color were allowed as were grey cars that had stenciling over and above the minimum requirements. These two volumes will be essential color references for modelers! Manufacturer: Morning Sun Books. Model Number: 8568. Availability: Ships in 4 to 10 Business Days. Trainz Product Id: 12735149.