Wrt a Spanish hub transtraxman. My logic to have this in Barcelona as opposed to Madrid is :
a) Although Madrid has double the population of Barcelona, Madrid is surrounded by the lowest population density, whereas Barcelona is surrounded by other higher population density areas.
b) There is far greater affluence in northern Spain. Northern Spain is recovering at a quicker rate and is expected to be the base of future growth in Spain. Central and southern Spain continues to deteriorate.
c) The proximity to southern France and its links with HS rail enable it to have a better catchment area than Madrid – imo.
d) Most potential Spokes would find BCN more accessible than MAD – especially with a high performing Vueling.
Thus would consider replacing MAD with BCN, especially if IB continues to be problematic.
As you have a better insight into the region, where should the hub be? Impact of any independence?