I know that many public transit services are (highly) subsidized, but it's a bit shocking to me that a) there is a huge demand for more capacity and b) it is si

I know that many public transit services are (highly) subsidized, but it's a bit shocking to me that a) there is a huge demand for more capacity and b) it is simply a matter of adding more trains. It would seem to me that this is an easy investment decision for local governments to make. Many other transit services can't simply add trains without making other investments like improving switching capacity so that trains can run closer together, lengthening platforms, or adding tracks around platforms so that express trains can jump ahead of trains stopped at a station. If your current trains are at capacity while the infrastructure is underutilized (and there is plenty of demand) that's just fantastic news.