| | California High Speed Rail Authority http://www.cahighspeedrail.com/ |
| | Canadian National (CN) http://www.cn.ca |
| | Canadian Pacific (CP RAIL) http://www.cprailway.com |
| | Canadian Transportation Agency http://www.cta-otc.gc.ca |
| | Canarail http://www.canarail.com |
| | Cargo Community System of Brazil (CCS) http://www.ccsbrasil.com.br |
| | Cargotrack http://www.cargotrack.com |
| | Center for Transportation and Environment (CTE) http://itre.ncsu.edu/cte/ |
| | Central Car Information System of Czech Railways (CEVIS) http://cevis.datis.cdrail.cz/ANGL/ |
| | Centre d´Etudes des Transports pour la Méditerranée Occidentale (CETMO) http://cetmo.org |
| | Centre Interdisciplinaire de Recherche en Transport et Affaires Internationales (CIRTAI) http://www.univ-lehavre.fr/labo/cirtai/cirtai.htm |
| | Centro Atl√°ntica http://www.centro-atlantica.com.br |
| | Centro Nacional de Capacitación Ferroviaria (CENACAF) http://www.cenacaf.com.ar |
| | CEPA http://www.cepa.gob.sv |
| | CFN http://www.cfn.com.br |
| | Channel Tunnel Rail Link http://www.ctrl.co.uk |
| | Chepe http://www.chepe.com.mx |
| | Chiltern Railways http://www.chilternrailways.co.uk |
| | China Academy of Railway Sciences (official) (CARS) http://www.cars.ac.cn |
| | China Academy of Railway Sciences (unofficial) (CARS) http://www.scsn.net/users/cluo/cars/ |
| | Chinese Railways (unofficial) (CR) http://severn.dmu.ac.uk/~mlp/crsg.html |
| | CI Preconcretos Rahs Ltda. http://www.preconcretos.com |
| | Club Ostheide (T3) http://home.t-online.de/home/05820678-0001/t3-club.htm |
| | Collaboration of railway police and security services (COLPOFER) http://www.colpofer.org |
| | College of Railway Technology, Derby http://www.rail.co.uk |
| | Combined Transport Ltd http://www.ctlctl.com |
| | Comisión Nacional de Regulación del Transporte de Argentina (CNRT) http://www.cnrt.gov.ar |
| | Community of European Railways (CCFE/ CER/ GEB) http://www.cer.be |
| | Compagnie de Chemins de Fer Départementaux (CFD) http://www.cfd.fr |
| | Companhia Brasileira de Trens Urbanos (CBTU) http://www.cbtu.gov.br |
| | Companhia de Transportes sobre trilhos do Estado do Rio de Janeiro (Rio Trilhos) http://www.riotrilhos.rj.gov.br |
| | Companhia Paulista de Trens Metropolitanos (CPTM) http://www.cptm.sp.gov.br |
| | Companhia Vale (EF Carajas and Vitoria a Minas) http://www.vale.com |
| | Comunidad Virtual del Transporte (LEGAZPI) http://legazpi.com |
| | Conrail http://www.conrail.com |
| | Conselleria de Infraestructures i Transportes de la Generalitat Valenciana (FGV) http://www.cit.gva.es/val/inici/ |
| | Construcciones y Auxiliares de Ferrocariles s.a. (CAF) http://www.caf.net/caste/home/index.php |
| | Container Corporation of India (CONCOR) http://www.concorindia.com |
| | Corridor Belifret) (BELIFRET (FREIGHTWAYS) http://www.belifret.lu |
| | Corridor Belifret) (CORRIDOR (FREIGHTWAYS) http://www.corridor.lu |
| | Corridor Belifret) (CORRIDOR FRET (FREIGHTWAYS) http://www.corridorfret.lu |
| | Council of Europe http://www.coe.fr |
| | Cummins Diesel SA http://www.cumminsdiesel.fr |
| | Czech Railways (CD) http://www.cdrail.cz |
