Openrailwaymap not functioning with openlayers2

Please pardon me if this is a stupid question, but I am trying since several days now to integrate a basic Openrailway map into a project using openlayers 2 API but it's simply not working. I followed all the steps mentioned [here][1] and ended up with something like this: http://codepen.io/payamcf/pen/XKPrvm What am I doing wrong? [1]: http://wiki.openstreetmap.org/wiki/OpenRailwayMap/API