Noni Gilbert Riley Apr 8, 2009:

Esclusas - for banks This seems to be what I was talking about in the bank context. Perhaps it might be applicable in this context too?

"Los sistemas de esclusas para acceder a una oficina bancaria son una de las fórmulas que ofrece más seguridad. El sistema se basa en encadenar dos accesos consecutivos en los que la persona debe acrreditarse. La apertura de los accesos es retardada para permitir decidir que actuación debe realizarse en caso de ataque a la seguridad de la oficina bancaria." http://www.accesor.com/esp/entidades_bancarias.php

Noni Gilbert Riley Apr 8, 2009:

My understanding of this ...is that when joining the transport, passengers have to pass through a security area, and likewise when leaving the transport. There is therefore a kind of "security insulation" in place. Don't know whether this area would actually be on the method of transport itself, or "on the ground". A bit like when you go into some banks in Spain. You open one door and that has to close behind you before the next door will open - I'm always wondering what this system is called...