When To Use Dry Transfers? When To Use Waterslide Decals?

If your simulated wood has a rough and uneven surface waterslide decals would be better.  The reason is a decal setting solution like Micro Set can be used to soften the decals and allow them to settle in to the depressions of the wood grain.

Waterslide decals are also better if your model has a soft surface like balsa wood as applying Dry transfers can cause depressions or small dents in soft surfaces. 

Charlie

Uneven surfaces such as the single sheathed boxcar above are better done with waterslide decals as Charlie noted. Additionally, if you are piecing together words or numbers, waterslide decals are much easier to place since you can slide them around while wet to achieve alignment.  With dry transfers, you are looking through frosted paper when you are trying to align them and you only get one shot.  Once you burnish them, you can't move them.

Bob

"A few pieces of rolling stock"?  "Individual numbers and letters"?  Dry transfer vs. water slide?

IMHO, a no-brainer.  Water slide.  Charlie and Bob are spot on.

Plus, I don't know about your dexterity, but as I come to the end of my septuagenarian years, there's no hope/use for dry transfers on any of my projects from here to fire-drop.

If the choice is about the desire to have no, zip, nada residual film evident after the lettering and seal coat, I picked at that standard 'nit' loooong ago.  Peace and tranquility are far more important than 'filmitis'.  I've learned a lot from the forum on how to minimize decal film.  I've lowered my own standards accordingly.  (The LHS guys long ago gave me the alternative moniker "Lucas Gudinov")

But, that's just me.  TEHO.

So, IIWM, faced with multiple cars of the same type as in your photo, I'd be looking for some custom water slide decal sets.  The forum's Scenery Source List has several possible sources.   I definitely wouldn't be looking to slide ONE letter or ONE digit at a time onto the model and keep everything set in proper spacing and alignment.  I'd have the artwork all laid out properly...and then make appropriate cuts to accommodate surface features, such as standing ribs/shapes.   Someday you might want to apply the same decals to less convoluted car side in a later effort...for which having the whole line...ELIZABETHPORT, f.i...intact would simplify the job.

FWIW, of course...

KD

Although I must agree on using waterslide in your particular case, I must defend dry transfers on otherwise smooth surfaces. I've redone some prewar with some dry transfer and they look good. Waterslide film showing on prewar resto's make them look amateurish.

Now if I was a manly man, I'd go with the stamps, but I'm not............