The troops only consume food resources, not the population of the city. Note added: When you build, consume foods as well.
Board game: Build houses and increase their income inactive gold and taxes.
Train troops requires not only resources but also of the inactive population. Once you have queued troops inactive population will decrease until the queue is finished. The inactive population to the tail of the troops will again be available to the queue for more!
NOTE: Do not go overboard on housing construction, 6 to 8 people maximum is ideal. You'll want to save room for fittings to grow your army faster.
More search does not mean they have a greater capacity for the troops. More Houses simply means that you can support your resource buildings in the countryside, the train lines of the troops at a time, and receive more tax revenue gold.
Board game: If the inactive population is reduced to zero when you are trying to train the troops, temporarily set your tax rate low. This will immediately increase the population is inactive. Tail of the training of troops, then the rate of income tax arrears for the best. (See theater.) Training will continue without any problems.
You can have several houses and garrisons, but no buildings in the city, so once you've built every one of the buildings, the question is how to divide the rest between home and fittings. The number of side lines controls the amount of training may have, thereby reducing the number of different queues that you want to juggle. One recommendation is to build six houses and fill the rest of the city with fittings to minimize training time and maximize the energy growth.