How does coupling between two trains work ?

The capacity of a rail convoy often needs to be adjusted to adapt to peak traffic.
Many trains have a fixed configuration. It is therefore necessary to resort to coupling between two trains:

Today, coupling or uncoupling is no longer carried out manually: it is directly controlled by the driver, using the control panel in the driver’s cab.
During coupling, one train approaches another at low speed to limit the effect of the “jolt”. They are then linked together by an automatic coupler, consisting of: mechanical systems to ensure the connection between the two trains, pneumatic ducts to guarantee continuity between the two trains, and finally, electrical connector heads to allow both trains to be controlled from a single cabin. To optimise aerodynamics, coupling systems are sometimes hidden away behind hatches.

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