Tomy Plarail C62 variations?

No, the brown bridge is only exclusive in the C62 set. The 2 white viaducts are found in the Hikari set. Names of sets are almost the same, except the train and contents.

[Super]

You are right Vio, my old brain just got the double white bridge set mixed up. What is nice about the brown bridge that the white bridge can not do is that the brown bridge does not need any risers to attach track on either side but the white ones do.

No Vio, there are only 100 Silver Thomas’...
No one seems to know how exactly how many Gold Thomas’ were made.
So far, I have only ever seen 2 at auction, and the other one was in very poor condition and did not sell.

You are right Vio, my old brain just got the double white bridge set mixed up. What is nice about the brown bridge that the white bridge can not do is that the brown bridge does not need any risers to attach track on either side but the white ones do.

Both bridges actually share the same mold, but different colour.

 

No Vio, there are only 100 Silver Thomas’...
No one seems to know how exactly how many Gold Thomas’ were made.
So far, I have only ever seen 2 at auction, and the other one was in very poor condition and did not sell.

I'm not a specialist in Thomas series so I got mixed up.
When are these produced?

[Super]

Both bridges actually share the same mold, but different colour.

Not exactly the same mold Vio. I am not sure about the cream colored bridge like these as I don't have one of those but there is a difference between the brown and white ones where the brown bridge can have a track connected on either end without the use of a riser/pier where the white one must have a riser/pier on each end. I could get you a picture if you would like to see the difference.

Looks like I need a picture. From here, it looks like 1 pier is needed on 1 end. There is another pier on the right side but not so close to the viaduct. This was picture taken by me in the Plarail Expo in Osaka 2019. On the right we have the set's box art.

[Super]

Here you go. I do like the how the brown one doesn't need any piers as it gives the bridge a more real look. You can see in the pictures that there are two nubs on one side and the opening on the other has a flat plate. These all hold up track without the need of a pier where with the white bridge the connecting track would just fall through without piers.

Wow, that is so cool. Again I got lectured. I don't have a brown and white to compare, probably you are the first to do this comparison.
These rails are called こうかレール, one of the most expensive rail parts. Also very very rare so what you have there is a treasure trove of research material.

[Super]

No lecture Vio, just sharing of info. Any time you don't have to use a yellow pier is a good thing in my book. I don't have any more of the old yellow, clip on, block piers to compare, just these white ones. I am curious which way the cream colored bridge is.

May I ask where and when did you find that white and brown bridge?