I have a D3s and and D800e and for railroad photography, I much prefer the D800e over the D3s. Also, I've have found that at 6400 iso I actually prefer the D800e over the D3s as the D800e files appera "richer" than the DSs, even the D3s migh be a hair less noisy. I think the extera resolution helps there. (Interior photos). I didn't think the D4 was that much of an improvement to sell the D3s and I found the D800e to be much better formore needs, so it's the go to camera now.