1. See pleading guilty won't be good option in your case till your confirm that court is not awarding sentence it will just award the fine which can be only judged by previous orders of that court in such cases. If court is of the view that if accuse plead guilty they put fine then you can go for it for sake a local lawyer can assist you. Further in your case amount is more so contesting is better option as in case of pleading guilty court can award sentence it is not.necessary it will only order fine..
Further the medical condition and all this are rarely considered as court finds everyone equal before eyes of law but yes they can persuade the court.
2. Further yes this is correct you can go for quashing on this ground before the high court that railway police was not authorized to file prosecution so the case has footing and the whole case against you has to be quashed.
https://www.google.com/url?sa=t&source=web&rct=j&url=http://highcourt.cg.gov.in/Afr/courtJudgementandAFR/2014/Sep/CRR37of4.pdf&ved=2ahUKEwit9Y-s8vrfAhULLI8KHTjbCI8QFjAFegQIBBAB&usg=AOvVaw1nbSvHRdxHo-Nm7Rb24VK9&cshid=[deleted]