Here are the settings of my final rendering for this project (the values that you can see in these images are the values that I used for the high-resolution version, at 4000*2000 pixels):
Fig. settings-rendering 1
Fig. settings-rendering 2
The post-production was done in Photoshop. I'll explain all of the effects that I applied on the image because there is a big difference between the image without the post-production and the final image.
Fig. underground-escalator without post-production
Before adjusting the brightness, contrast and colour, I did some corrections on the reflection.
After the rendering I had some noise on the metal on the interior side of the escalator, and I used the tool stamp to remake a good reflection. You can see the correction made in the following images.
Fig. Corrected Reflection
So, for the first step in my post-production work, I applied a "levels" layer to adjust the brightness and contrast (I'll improve it later with others layers, too).
Next, I duplicated the layer with the levels and applied a blur at 10-15 to the image. I made this effect so I could obtain a slight glow on the entire image, and to darken some parts of the image as well. I set this layer to either "overlay" or "soft light", and I played with the opacity of it, too.