I am using opentripplanner for an app development. I want to customize the webapp. It has many different maplayers (its using openlayers). I want to change some mapslayers, but i couldn't find in which java-script file they are creating map and maplayers.
The entry point for adding map layers is in the Controller. On line 56, the map controller is created:
this.map = new otp.core.Map(this.config.map);
this.map.getMap(), will give you the OpenLayers.Map object. You're on your own from here, as we haven't really built api support for adding new layers to the map.
This answer was found here and modified a little bit.