Beckton depot and Dagenham Dock extension

That siding/headshunt is at ground level, as are all the tracks within the depot.

By the by, the Google Earth image is now somewhat out-of-date, as there are lots of new sidings to the south of the main depot building to accommodate the new trains- and there is now a level-crossing at the entrance of the depot (where the line crosses the access road from the roundabout on Armarda Way) that links the siding/headshunt you mentioned (which presumably can't be called that any more) to all these new sidings. I'm not sure if there's a connection at the eastern end of these new sidings to the line that's used to access the depot.

So that's a nice oddity for you - a level-crossing on the DLR! I presume that trains are driven across it in manual mode, but I don't know that for sure.

However do note this - this unusual level crossing is completely within the depot site, past the main access gate and guard house - it's not on a public road and you can't get close in to see it either.

It will however show up on the aerial views of Google Earth/Maps and other online map services eventually!