Hold True

I was thinking about this verse from Philippians 3

¹⁶Only let us hold true to what we have attained.

and the analogy and image that came to mind is a cog railroad. I remember when we lived in Germany taking a cog train.

From Wikipedia:

A cog railway, pens and rails railway, rack-and-pinion railway or rack railway is a railway with a toothed rack rail, usually between the running rails. The trains are fitted with one or more cog wheels or pinions that mesh with this rack rail. This allows the trains to operate on steep gradients.