Non GTFS to GTFS data conversion using FME

Working on FME v15515 build with 8gb ram, win7. I am testing my work for the generation of GTFS data for London city by generating APIs from here. I have my App Id and App Key with me. As I provide the Id or other required fields, an API is generated. I use this API in FME (using HTTP caller(get)) and generate the output in JSON/XML format. Although, I am able to save this info correctly but not sure how exactly to manipulate it. For the complete GTFS data, we must have 5 required files including stops, stop_times, calender, routes and agency. The data which I have now, after saving in XML format seems to have not the complete info. Do I need to get other files as well from the same site source. Are there any other possible ways to automatically download the data and convert it from APIs to GTFS data. pfa the output what I have got by the wb-

My question is, is the information correct what I have got as an output of the FME? Will all the text/csv files be generating with the output which I have got? Or do I need to change the whole process? Why do I need to do that- I have a century of cities to work on for Transit Feeds. Some of the cities already have prepared GTFS source but for some, we need to create using APIs.