Manuel could share his bedroom

Question

Although the note on the question suggests the imperfect of Poder I think the translation should use the conditional, Podría rather than podía

Accepted Answer

Hola Maggi
we could also say as you suggest
Manuel podría compartir su habitación.
This is also grammatically correct, but the meaning is different. With "podría" we are expressing a hypothetical situation: "he could share it, that is a possibility", but with:
Manuel podía compartir su habitación 
what we mean is "he actually could/was able to" - a past action, not hypothetical.
Here is a lesson that explains this meaning of a hypothetical "could" in Spanish. Have a look here.
Saludos
Inma

Answer

So to clarify, if as per your example we say "Ellos podían coger el metro" this would mean 'they could take the train' (as in... in the past, they could take the train) whereas "Ellos podrían coger el metro" would mean 'they could take the train' (as in... why don't they take the train, as a suggestion)...