I too would be concerned about the strength of the shelves. Model trains have much higher density and weigh a lot more than shoes. I wonder if a model train has a higher density than its full-scale counterpart?
Multiply the weight of a given model by 48^3 (110592) and compare the result to the weight of it's actual counterpart. I'm using a rough argument that since the model is 1/48, it would take 48 of them in all 3 dimensions (l x w x h) to fill a similar volume of the real thing. (Possibly a bit of a flawed argument, so feel free to poke holes in it .)
That should be close enough for such a curiosity.
Let's guess a model scale GG1 weight about 15 lbs (I guessed, feel free to use the correct number). 15 x 110592 = 1,658,880 lbs.
If Wikipedia is correct (replace with your favorite more accurate railroad reference), it claims a GG1 weighed 475,000 lbs.
Looks like the answer may be yes! (YMMV, and specific models may vary).
As to the shoe shelves, I'm not sure I would want them for myself, but I am sure they could be made to look good in some instances.