The running track was on top of the already constructed now 1st tier ! The open end which became the North Stand was purposely left open to allow the site access for the equipment to finish the stadium to be converted into the football ground ! The first tier is 4 meters below ground level.One thing I've sometimes wondered is whether the first tier where the running track is was dug out as part of the original works and the running track put over it or whether the whole first tier, concourse etc was done afterwards, that would be a very big job. Anyone know what happened?