Actually when Dangoaposi station was built 1920 by Premji Khengar, there were only two lines and the station was built on one side. So the station was built by the side of up line and there was one platform only, which is presently platform no. 2. The down line had no platform. Later when major yard was built here, many lines were built on both sides of the station, then platform no. 1 was built on the other side. After building of the RRI, all the lines became bi directional and trains began travelling in both directions on all the lines. Platform no. 2 is the main platform here and so, if it is vacant, all the trains are placed in platform no. 2 irrespective of whether they are going up or down. So, Howrah Barbil Janshatabdi Express always gets to halt in platform no. 2 whether it is going up...
more... or down. But Tata Gua DEMU always gets platform no. 1 in both directions for a reason. It refills diesel daily at Dangoaposi in the front engine while going to Gua and while returning it refills diesel in the other engine. Since diesel refilling system has been built only in platform no. 1, so it always stands in platform no. 1 in both directions. While returning, it stands in platform no. 2, only if it has not to refuel itself that day.