If I was redesiging a big station then the departures "drop off" would be directly above the arrivals "pick up" as it would be at an airport. This is the same way that the Chinese HSR system works at all new stations (as far as I can tell, I have only really used Beijing South, Tianjin, Shanghai South, Shanghai Hongqiao, Jiaxing South, Guangzhou and Shenzhen).
I assume that the levels of commu(nis)ters
using these stations are at least on par with all but a few main stations in (some) of the European countries. Of course the amount of land space for traffic spread and parking (except for level change arrangements) can be reduced that way, but otherwise works flow-wise and for arrangements largely only for new station designs.
When you are integrating transport this is also clever because the buses can drop off at the departures area but then have a more "bus station" type arrangement to pick up near the arrivals.
Different drop-off and pick-up stops for buses must be already in use in most bus stations, but even then there is only a single entrance to a connected rail station.
However you can have multiple entrances and exits they just lead to (come from) different places. [...] There need be no confusion as routes for exit would be clearly identified as no entry while all signs point to the entrance.
But these different entrances towards a station from across the tracks etc. still use bidirectional traffic low and entrances, as the split is only due to gaining access to the station from different streets and cul-de-sacs. Similarly, if the entrances and exits (of which there can be several from different directions) are somewhat next door (pun intended) to each other, then it would be orientation-wise workable.
Like I earlier stated, the internal arrangements as well as, not at all unimportantly, the car-dependent entrance to the area in the first place dictate the entrance/exit locations at airports. Rarely a pedestrian approaches an airport from one of several directions on foot, expecting this or that street leading towards the airport to feature an entrance somewhat nearby. Mainly because there is no such street as in the case of a rail station that in many cases is located within a streetscape. Stations with strictly one approach of course excepted, but then they are not unlike airports in that sense anyway.
If you use the Jiaxing South example then there is an escalator up from the arrival level to the departure level but no escalator down. Immediately it is obvious which one is the entrance level and which is the exit. Similar things would give it away to most people.
Or you could push your way towards the escies, see that some m*ron has switched it for one-way-running (as per peak traffic direction) and take the lift to the lower hall anyway. And only
then realize the true nature of things... But these out-of-ordinary arrangements are situations where the signage plays a vital role. A bit like getting to the domestic platforms at STP...
Barriers bring us to the final point, they are easier if they are single direction. The criticism of KGX is that people arriving and people wishing to board at the next platform will clog the system. But if the arrivals had gone down to a level underneath they would not be in the way...
If "retrofitted", such a two-level approach requires rather heavy changes to the existing building and the appropriate changes will extend to the outside too, not necessarily in a beautifying sense.
(even commuter stations are almost completely one way flow - out in the morning back in the evening - and so would not need to be ammended too much).
If modifying existing smaller stations, why the difficulty of providing barriers (that would have to be bi-directional due to the ebb/flow nature of peak traffic in order to not lose half the barrier capacity) or different halls and traffic courts (again, one fully used while, at the same time, the other sits almost unused)?
A final example. If I was going to barrier Manchester Piccadilly I would upgrade the bridge on the departure end of the platform and have all arrivals cross that to then come down the travelator. People wishing to board a train would then come from the appropriate glass door through a barrier to their train. (The bridge is certainly wide enough it would just need escalators and lifts from all platforms) Yes it would be inconvenient but connections across the buffer stops* and over the bridge would be easy, there is not too much extra movement required by passengers.
I'm afraid I'm lost there as I've only used it once and don't know what the change entails, but is departure end the departure (shed "mouth") end of the train or what... Hmm, NR site:
http://www.nationalrail.co.uk/stations/sjp/MAN/plan.html?rtnloc=MAN Oh dear.
So all exit from platforms is after a long walk (or travelator-trip, if someone pays for such a cadget) along the side platforms via the bridge? Not so appropriate if you'd want to leave that 1st Class coach already nearest the concourse.
But if the bridge is to be bi-directional and barriered, for capacity reasons the exit escalator/stair (or escalator/escalator) combination would have to be double-width to accommodate all the exit traffic from, at worst, two trains at the same time. On top of that there would of course have to be an extra, barriered stair or escalator for entrance to the respective platform. Plus the lift from the bridge. If using different sides of the bridge, all these could be most probably accommodated.
But then again the question of traffic flow direction arises - is in this local hub station, for example, any
real need to force the entering and exiting traffic to use different routes, rather than using the bridge for only arrivals relief in peak times, similarly with departures. Thus both buffer end and bridge would be bi-directional - ie. in peak times mostly for traffic in a single direction. At the bridge there would be single, barriered one-way escalators for both directions, whereas the buffer end would be bi-directional as required by the traffic flow. So, the case KGX wins here too...
