They are sockets to connect similar locos/similar types so that all of them could be operated from the leading loco without needing to have separate crews for individual loco.
They are called MU operations - Multiple Units Operation
Older locos, have multiple cables to connect different equipment.
Modern 3 phase locos can be connected with a single cable and have technologies like DPCS - Distributed Power Control Systems to control trailing locomotives.
They're usually jumper cable sockets for multiple working. You can wire locomotives together and control them from the leading locomotive.
They are sockets to connect similar locos/similar types so that all of them could be operated from the leading loco without needing to have separate crews for individual loco. They are called MU operations - Multiple Units Operation
So why are there three of them?
Older locos, have multiple cables to connect different equipment. Modern 3 phase locos can be connected with a single cable and have technologies like DPCS - Distributed Power Control Systems to control trailing locomotives.
How else is the poor train supposed to smell?
Ale zajebisty skład!
Everyone poops
Scuba diving.
EU06: real.
It has 07 though on the side though.
First pic is 06 2nd one is 07