Lisbon metro

We arrived at the underground station just after six on a weekday morning, much to my astonishment, the network is still closed, gates were locked and the lights switched off.

As 6.30 rolled around, the lights were switched on, the doors opened and we then strugged to purchase two one way tickets to the airport, some help was rendered by the lone staff member working. When people wandered into the station; every passenger had either a backpack, a bag slung over their shoulder or wheeled their bag in. The morning metro clientele was all destined for the airport, as were we.

We headed down to the platform; I questioned if we had the right train, it was headed in the wrong direction as the European trains select the right track as they drive on the right hand side of the road. I rechecked the direction against the metro map, we were heading in the correct direction - nothing to worry about apparently,  yet I was.

As the train pulled into the station, my fears were allayed, the direction was correct; the Lisbon metro runs on the left hand track - just as the London undergroung does. This begs the question, why does the Lisbon, and I guess, the Portuguese system utilise the left track when vehicles use the right lane?

Was the system designed and built by the British?

Are rail cars and carriages similar to the London underground?

I never used the Porto metro, is this system designed in the same fashion?