The railway ran parallel to Magazine Road in a rock cutting, and split into two branches - one rising on a gradient up to the junction of Thermal Road and Stadium Road and turning right at 'Port Rainbow'/Brotherton's Factory to continue to The Margarine works and Bromborough power station at the side of Stadium Road.

The other line continued in the cutting, passed under Thermal Road, and continued to Bromborough Dock - not the bit shown in your third photo (which was Magazine Village), but to the main dock futher along (near Dock Road South today).

I've only got details of this last bit handy at the moment, but as has been already stated, 'The 'Railways of Port Sunlight and Bromborough Port' book are recommended reading.

The two views I have added show the the aerial, and then overlaid with what used to be there - the line can be seen swinging away from Magazine Village left towards Bromborough Dock.