Another interesting aspect of Victorian railways: Originally, passenger coaches had compartments spanning the full width of the coach with doors on both sides, typically with room for 8 passengers. While this puts a maximum of passengers in a coach, each of the compartments is totally isolated and there is no shared infrastructure, like bathrooms or a chance to collect any sort of food, etc. Hence the train has to increase halts at stations to allow for any passenger needs (which may also collect a bit of extra profit at the stations). At some point, coaches with corridors where introduced, now offering room for just 6 passengers in any of the compartments. A drop of 25% in capacity! on the other hand, based on average speeds and frequency on your network, you may more than compensate for this by less frequent and shorter stops, by this increasing overall throughput of the system. Where is the exact point in the evolution of technology, of your system, and of market acceptance that this becomes a viable option? (Include any losses on side business at the stations in your considerations.)

I once saw a humble, but quite astounding artefact on TV: a box for mailing eggs, of course, Victorian. Behind this hides an entire system of postal service and mail train delivery. A, say, Cornish farmer would put fresh eggs for an individual customer in said box in the early morning. Those boxes were then collected by the postal service and shipped by train to London, where it was delivered to the customer's home, just in time for breakfast, the very same morning. (Amazon next day delivery pales in comparison.)