Note that there is an underlying theme in most of the questions. If you understand this theme it will help.
- What do these stations have in common? For the bottom one, go by the sign you can see rather than the station name. Click to enlarge.
A: They are zonal headquarters but not divisional headquarters. The HQ of SER is near Howrah but there is no Howrah division of SER. In fact SER is a guest of ER at Howrah. (However, there is an Howrah division of ER). Similarly for Hajipur, Gorakhpur and Maligaon (in Guwahati city).
2. What connects the first 4 stations here? And what connected the 5th (bottom right) to the first 4 later?
A: SC, BZA, SUR and UBL were the original constituents of SCR when it was formed in 1966. SC and SUR were in CR, BZA and UBL in SR. After a few years SUR was moved back to CR and GTL was moved from SR to SCR.
3. What unusual feature does this station have (considering the above theme):
A: Nagpur is in CR and the SECR joins there. There is a Nagpur division both in CR and SECR. Like SER in Howrah, SECR does not own the Nagpur station.
4. What unusual features do these stations have (again, considering the above theme plus something else):
A: Chakradharpur, Danapur, Nanded and Izatnagar are divisional headquarters which are not junctions. Note: Izat is correct, not Izzat although even local people get this wrong.
5. The same theme, but somewhat different. What connects these stations? Think of pre-independence days.
A: Baroda, Gwalior, Trichnopoly and Jodhpur were zonal headquarters in the past but not now: for the Gaekwad of Baroda’s State Railway, Scindia State Railway, South Indian Railway and Jodhpur State Railway. Other examples include Bikaner, Mysore, Jaipur and several others.
Note: the best attempt was by Santosh Kulkarni, also known as Sant Kulk.