Train routing help needed

[Hatsjer]

I managed to successfully setup a track which could support 2 trains for running oil, but I quickly found out that the trains were transporting the oil faster than it was extracted, so I set one of the two trains to manual, as I wanted to keep it on the track. But now the first train won't run as the second train is blocking it, despite the first train has an other route to go. How can I have one train running back and forth while having the other train on the track and ready to go at all times?
Link to imgur album: https://imgur.com/a/iiZU5mc

(I tried to get the pictures within a spoiler, but couldn't get it to work.
Also, I know I have too many signals, but don't know which one to remove.)

Bilde 1.png (885.9 KiB) Viewed 1869 times

Bilde 2.png (584.83 KiB) Viewed 1869 times

Bilde 3.png (887.7 KiB) Viewed 1869 times

Bilde 4.png (1.19 MiB) Viewed 1869 times

[Loewchen]

The offset signals in Bilde 3 and 4 mean the north west part of the track is unusable in either direction.

[Hatsjer]

The offset signals in Bilde 3 and 4 mean the north west part of the track is unusable in either direction.

Which one is the offset one? Left or right in the top, middle or bottom?
(Also, Bilde is Norwegian for Picture.)

[DaleStan]

The easiest way to find the offset signals is to hover your mouse over each currently-built rail signal, one at a time. Is another signal highlighted in green when you do that?
If yes, you are looking at pair of two-way signals. Trains can pass both signals in both directions.
If no, you are looking at a one-way signal. Trains can only pass that signal in the direction the arrows point.

If you have a one-way signal, but want trains to travel on that track in both directions, place a signal in the position marked in white. If there is no white position, remove the signal. If necessary, replace it further from the switch.

[Hatsjer]

The easiest way to find the offset signals is to hover your mouse over each currently-built rail signal, one at a time. Is another signal highlighted in green when you do that?
If yes, you are looking at pair of two-way signals. Trains can pass both signals in both directions.
If no, you are looking at a one-way signal. Trains can only pass that signal in the direction the arrows point.

If you have a one-way signal, but want trains to travel on that track in both directions, place a signal in the position marked in white. If there is no white position, remove the signal. If necessary, replace it further from the switch.

Found it and fixed it. Thank you so much for your help!