Note: Marks ending in U are for container owners; marks ending in X are not common carriers; marks ending in Z are for trailers without flanged wheels. All other marks are of common-carrier railroads.

D

• DA - Dominion Atlantic Railway; Canadian Pacific Railway
• DACX - Darling and Company; VIP Tank Services
• DAFU - Dafra Lines, SA
• DAFX - United States Department of Defense (Troop Support and Aviation Material Readiness)
• DAFZ - Dafra Lines, SA
• DAIR - D&I Railroad
• DAKR - Dakota Rail
• DAKS - Dakota Short Line
• DAKX - DAK Americas, LLC
• DALT - Dallas Terminal Railway
• DALZ - D and A Leasing, Inc.
• DANX - Dana Railcare
• DAPX - Dairyland Power Cooperative
• DARU - Dart Container Line, Inc.
• DARZ - Dart Intermodal, Inc.
• DATU - Dart Container Line, Inc.
• DATX - DATX Associates
• DAVX - W. R. Grace and Company (Conn. Davison Chemical Division)
• DAWX - D.A. Walmsley and Company
• DAX - Diamond Shamrock Chemicals Company; Occidental Chemical Corporation
• DBCX - Badische Corporation; BASF Corporation
• DBGX - Dowdle Butane Gas Company
• DBSU - Donbar Steamship Company, Inc.
• DBUX - Canterra Energy, Ltd.; CIT Group/Capital Finance, Inc.
• DBWX - DB Western, Inc.
• DC - Delray Connecting Railroad
• DCAX - Tarmac Florida, Inc.
• DCBX - DeGussa Engineered Carbons, LLP
• DCCU - Dow Corning Corporation
• DCCX - McDonnell Douglas Corporation
• DCFX - PLM International, Inc.
• DCI - Des Moines and Central Iowa
• DCIX - Danella Construction Corporation
• DCLR - Delaware Coast Line Railroad
• DCLU - Dutch Container Leasing, B.V.
• DCLX - Procor Ltd.; Dow Chemical Canada, Inc.
• DCMX - Davidson Construction Materials, Inc.
• DCON - Detroit Connecting Railroad Company
• DCOU - Dow Corning Corporation
• DCPX - Dart Container Corporation of Pennsylvania
• DCR - Delmarva Central Railroad
• DCRR - Dubois County Railroad
• DCSU - Delta Conteneur Service
• DCTX - PLM International
• DD - Dover and Delaware River Railroad
• DDDX - Frontier Cooperative Company
• DDEX - Dupont Dow Elastomers, LLC
• DDNX - Didion, Inc.
• DEAX - Deacero, S.A. de C.V.
• DEBX - Ceres AG Products
• DEEX - Detroit Edison
• DEGX - Mississippi Power Company
• DEMX - Demeter, Inc.
• DEPX - Dependable Properties, Inc.
• DETX - Detroit Edison Company
• DFTX - DTE Transportation Services, Ltd.
• DGBY - Digby Truck Lines
• DGCX - Dakota Gasification Company
• DGHX - North American Chemical Company
• DGIX - D and G Enterprises, LLC
• DGNO - Dallas, Garland and Northeastern Railroad
• DGVR - Durbin and Greenbrier Valley Railroad
• DH - Delaware and Hudson Railway
• DHNY - Delaware and Hudson Railway
• DHPX - Degussa Corporation
• DHRU - Den Hartogh NV
• DICX - Pure Carbonic Company
• DIIU - Dart Intermodal, Inc.
• DJBX - Gandy Dancer, Inc. (Donald J. Bertel)
• DJJX - The David J. Joseph Co.
• DJLX - The David J. Joseph Co.; CIT Group/Capital Finance, Inc.
• DJMX - Daniel John Marnell
• DJNX - The David J. Joseph Co.
• DJPX - The David J. Joseph Co.
• DJRX - The David J. Joseph Co.
• DJTX - The David J. Joseph Co.
• DKPX - Duke Power Company (scale test cars)
• DKS - Doniphan, Kensett and Searcy Railway; Union Pacific Railroad
• DKUX - Exxon Mobil Corporation
• DL - Delaware Lackawanna
• DLC - Drummond Lighterage
• DLCR - Delaware Coast Line Railroad
• DLCX - Waste Management, Inc.
• DLFX - Diversified Lease Funding, Inc.
• DLGX - Lewis Grain Company
• DLKU - Deltank, Ltd.
• DLMX - Daylight Locomotives and Machine Works, Inc.
• DLNW - Denver, Laramie and North Western Railroad; Great Western Railway of Colorado
• DLPX - DeGussa Canada, Ltd.
• DLRX - GE Railcar Services Corporation
• DLSX - Diesel Supply Company, Inc.
• DLTX - Dale L. Thornborough
• DLVX - Thiokol Corporation
• DLW - Delaware, Lackawanna and Western Railroad; Erie Lackawanna Railway; Norfolk Southern
• DLWR - Depew, Lancaster and Western Railroad
• DLWX - D.L. and W., Inc.
• DM - Detroit and Mackinac Railway
• DME - Dakota, Minnesota and Eastern Railroad
• DMHX - Davenport Mammoet, LLC
• DMIR - Duluth, Missabe and Iron Range Railway
• DMIX - ADM Transportation
• DMLX - GE Railcar Services Corporation
• DMLZ - DML Containers
• DMM - Dansville and Mount Morris Railroad
• DMU - Des Moines Union Railway
• DMVW - Dakota, Missouri Valley and Western Railroad
• DNAX - Dana Railcare
• DNE - Duluth and Northeastern Railroad
• DOCX - Du Pont Canada, Inc.
• DODU - United States Department of Defense
• DODX - United States Department of Defense (Military Traffic Management Command)
• DODZ - United States Department of Defense
• DOEX - Doe Run Resources Corporation
• DOLX - Dolese Brothers Company
• DONX - Donnelly Commodities Company
• DOTX - United States Department of Transportation; Federal Railroad Administration
• DOWU - Dow Chemical Company
• DOWX - Dow Chemical Company
• DPCX - Blue Circle, Inc.
• DPDZ - Delaware and Hudson Railway
• DPGX - Tractech Systems
• DPIX - Dufour Petroleum, Inc.
• DPLX - Davenport Cement Company
• DQE - De Queen and Eastern Railroad
• DR - Dardanelle and Russellville Railroad
• DRAX - DRAYCUTT Corporation
• DRCX - Martin Marietta Corporation
• DRDX - The Duredo Company
• DREX - ProTrade Steel Company
• DRG - Denver and Rio Grande Railroad
• DRGW - Denver and Rio Grande Western Railroad; Southern Pacific Railroad; Union Pacific Railroad
• DRGX - Denver and Royal Gorge Railway
• DRHY - Durham Transport
• DRI - Davenport, Rock Island and North Western Railway
• DRIR - Denver Rock Island Railroad
• DRMX - Danbury Railway Museum
• DRR - Delaware and Raritan River Railroad
• DRR - Disneyland Railroad
• DRRV - Dover and Rockaway River Railroad
• DRSX - D.O.T. Rail Services, Inc.
• DRTU - Dart Intermodal, Inc.
• DRTZ - Dart Intermodal, Inc.
• DSBU - Ameribrom, Inc.
• DSCX - DIFCO, Inc.
• DSDX - Pullman Leasing Company
• DSEX - East Carbon Development Company
• DSIX - Dowell Schlumberger, Inc.
• DSLX - DeGussa Corporation
• DSLZ - Intermodal Services, Inc.
• DSRC - Dakota Southern Railway
• DSRR - Delta Southern Railroad
• DSRX - Downeast Scenic Railroad (and its parent organization, Downeast Rail Heritage Preservation Trust, Inc.)
• DSSA - Duluth, South Shore and Atlantic Railway
• DSSX - Detroit Salt Company, LLC
• DT - Decatur Junction Railway
• DTCX - DTE Transportation Services, Inc.
• DTEX - Dresser Transportation Equipment (Division of Dresser Industries)
• DTI - Detroit, Toledo and Ironton Railroad; Grand Trunk Western Railroad; Canadian National Railway
• DTIZ - Grand Trunk Western Railroad; Canadian National Railway
• DTLX - Delta Tank Line Company
• DTRR - Danbury Terminal Railroad; Housatonic Railroad
• DTS - Detroit and Toledo Shore Line Railroad; Grand Trunk Western Railroad; Canadian National Railway
• DTTX - TTX Corporation
• DTZZ - Direct Transit, Inc.
• DUCX - DuPont Canada, Inc.
• DUFX - Duffy and Sons, Inc.
• DUKX - Dupps Company
• DUPX - DuPont
• DUT - Denver Union Terminal Railway
• DUTC - Dallas Union Terminal
• DV - Delaware Valley Railway
• DVLX - Duval Corporation; Freeport-McRo-Ran Sulphur Company
• DVR - Devco Railway; Cape Breton Development Corporation (Coal Division); Sydney Coal Railway (its successor)
• DVRU - Dover, Ltd.
• DVS - Delta Valley and Southern Railway
• DVSZ - Delta Valley and Southern Railway
• DVTX - SULCOM, Inc.
• DW - Detroit and Western
• DWAU - Degussa Antwerpen, NV
• DWC - Duluth, Winnipeg and Pacific Railway; Canadian National Railway
• DWCX - David Witherspoon, Inc.
• DWML - Due West Motor Line
• DWP - Duluth, Winnipeg and Pacific Railway; Canadian National Railway
• DYLX - Ronald L. Boothman Remainder Trust; Transportation Equipment
• DYNX - Dyno Nobel, Inc.
• DYRX - Dynamic Rail Preservation Inc.