Offline Map Geocoding / Reverse Geocoding


Our application is a data collection app on transits like rail and buses. We collect information from people about their trip like
where they started ?
where they are heading to?
where they live ? etc

We used google maps to geocode / reverse geocode and provide search operations on Maps to collect above information and it works perfect.

But recently we came into situations where Rails are going through tunnels and in those areas, there is no internet or GPS reception.
So started using simple XAMP container on Android devices to run our web based application on that but the mapping, geocoding/rev geocoding is history now in absence of reception.

While looking for solutions I came across information where it is mentioned that we can store Map Tiles and use them in absence of Internet but again nowhere I could find a post, where they have used Search / Geocoding on such Offline Map Tiles.

So moved to open streets and it looks promising for our specifications.

I would really appreciate any guidance / suggestions on Feasibility and Implementation of the mentioned.