Ben M
Model railway track would be 1:87. However note some model railway types hand-lay track, so components are available to build your own in 1:72.

Treehugger
@Simon Key
Edit: (I corrected Code 140 to Code 143 below)

Hello
First question to you : Have you already bought this kit?
Ah, seeing that you have this in your stash, I guess you have.
This is all problematic, but I have some ideas.

Several problems:
1) Track gauge = width between the two rails
2) Rail profile = You will want a 'flat bottom rail'
3) Gauge = size for scale modeling. I think the appropriate gauge for 1:72 is Gauge OO (from memory, not 100% sure)
4) Code = rail height for train hobby
5) Track fasteners. The kit uses fasteners that is molded into the ground part, but creates for some slack/hole if adding Code 143 metal flat bottom rails, instead of the kit's 5mm tall rails (iirc).

Btw, for the Peco Code 143 product, you can also buy separate fasteners for the metal rails. But only for Code 143 but not Code 100 (the smaller rails).

My investigation indicate that the ideal gauge is CODE 100 (but kit wheels ought to be smaller anyway so, better with Code 143). An alternative would be CODE 143. Iirc, Code 100 = 0.1 inch and code 143 = 0.143 inch.

The product code for the loose/separeate Peco Code 143 flat bottom metal rails is IL-7FB if you want to investigate further.

Treehugger
What you can do, is to either buy loose Code 140 flat bottom rails, and somehow attach them onto the plastic parts (the original rails are overly large, and also their fixtures), or, possibly cannibalize flexi track rails, that has the wooden blocks in plastic included (but are too narrow).

Toy trains, iirc, typically have a too narrow track gauge, so too narrow for the 1:72 kit.

I will be using Code 100 flat bottom rails, and I have bought them. I also have 6 loose x Code 140 flat bottom rails, that I don't need anymore, but probably cheaper buying them locally as shipping perhaps has to be done by expensive courier service. I may want to keep my 140 rails if they fit for 1:35 projects, haven't thought about that yet.

This is a weird kit imo, but some easy fixes can be done (the fixes offer only the most basic aesthetic improvements). I think Code 140 rails might look ok with the kit's wheels.

I have lots of advice, but you might not want to hear them. 😄 Bascially, you will want to adjust the placement of the 8 small carriages, and maybe shorten the barrel, and be happy with that.

Treehugger
"Would it be possible to cut out the individual sleepers and mount them separately?"

Unfortunately, the wooden sleepers in the kit is molded into the base, together with the fasteners. If somehow finding the patience to cut off the molded sleepers, you get a hole in the rest of the base.

Treehugger
I guess, one could somehow use the existing base, add real pebbles/sand, and somehow add custom made sleepers, and hide them with real pebbles/sand. It is somewhat difficult figuring out exactly how you want to change things around.

Simon Key
Lots of ideas to mule over Treehugger, many thanks my friend.