Hark, yonder little englander rail enthusiast:
*mumble mumble* bloody EU» *mumble mumble* brexit will stop this Brussels meddling with our British† trains. *mumble mumble*
† Built in Japan, Spain, Germany, Italy.
Reading Today's Railways Europe it is interesting to see how many continental locos don't prominently display the the full ENV number or even the class number. This is particularly true of independent freight operators/loco lessors who seem to have their own numbering schemes. To confuse things further locos are often renumbered when changing owners. It makes train spotting interesting trying to keep up with these changes.
The ENV number is I believe supposed to be for life, so the loco can be tracked throughout its life
Some of the more interesting signage on locos is the country matrix with the country codes in which the loco/unit is authorised to run. It gets quite interesting on 4 voltage locos.
I also believe that
CIE» uses ENV codes even if there is no chance of interoperability with Europe.