Who has broken the railway line between Lagos–Ibadan and why no one has cared? (LINK)
Nobody.
What seems to have happened here is that the high resolution aerial imagery has run out, and it is impossible to follow the track of the railway just using satellite images. If you invoke the editor, with Bing imagery as background, you will see the upper part of the track runs out exactly at the boundary between a low altitude aerial image and a satellite one.
There are about four legitimate ways in which it might be mapped:
- There is sufficiently good aerial imagery that has been donated to OSM that the course of the railway can be followed on that, by armchair mappers;
- Someone has travelled on the line with a live GPS receiver, or has otherwise surveyed the course on the ground, and has edited the map to include their findings
- The Nigerian government or railway company have donated maps with a suitably liberal copyright licence;
- It exists on an out of copyright map that an be traced, preferably one that is available on line, and has been properly georeferenced.
As to why no-one cares, OSM seems to find it difficult to find local people interested in contributing to the map outside of the rich, largely Western, world. This is probably why (2) hasn’t happened. I think you will find most mapping is armchair mapping done from Europe or the USA, or has been done by ex-patriots, from Europe or the USA.
I’m not sure how well aware that African governments are about making government information freely usable. Given that there are few users in their countries, it might not be something that interests them. As Nigeria has an insurgency problem and relatively recent civil wars, there may also be security concerns about providing accurate infrastructure mapping.
If you want the missing section mapped, you need to convince the smart phone owners of Owowo Market to install mapping software, take a journey on the train and then contribute the result to OSM.