How is lettering applied to locomotives and rolling stock manufactured today?

The most common method used is pad printing, where a silicone pad with the desired pattern is pressed against the shell usually by an air cylinder.   The machines are relatively simple, as the parts tend to be loaded and unloaded into the fixture one at a time by an operator.  Multiple colors require separate pads and may be done across multiple single pad machines.  Sometimes turret or linear mechanisms can move the workpiece between applicators.

Making and maintaining the pads and running the machines tends to be labor intensive, adding to the reasons why our trains tend to come from Asia.

Another option, which I believe Lionel uses on their US made products done in Concord, is UV inkjet printing.  The process is pretty much the same as what happens on a home inkjet printer, except that the inks and the heads which apply them are much more expensive.  I used to work for a company which built machines around a Konica/Minolta uv print engine and the heads were over 2k apiece.  But, you can put 4 heads inline and with 4 colors (cyan, yellow, magenta and black) and really good motion control you could do full color prints in 1 pass. 

The head assembly moves over the work in linear passes like a home printer does, just on a much larger scale.  The inks cure quickly under a powerful UV lamp which can move with the head assembly or be a separate stage of the machine.

The equipment is much more expensive, but with multiple shells in the fixture and full color in only 1 pass it's an option when your labor costs tend to be higher.

There may be other methods, but these are the only options I know of for applying print to the irregular surfaces of a body shell at production rates.

Nick C.

Rusty

Mike Wolf toured the MTH factories and in the live-streamed video showed that a machine printed the complex, colorful graphics on RailKing freight cars.

You might be able to find that video on a website.

Andrew

Just to clarify a bit...

I believe in the pad printing process the ink image is acquired from the flat, etched plate which has previously been 'inked'.  The silicone pad itself is smooth.  it simply acquires the ink image from the plate and transfers it to the work piece.  The tooling costs are in the creation of the several etched plates, each one for separate colors and their contribution to the total image.   For the multi-colored image in the ScaleTrains video, the key time-consuming set up is in getting the registration of the layers precisely aligned.   The greater the image complexity and number of separate ink applications, the more costly the finishing process.

Nonetheless, pad printing far exceeds flexibility, cost, and quality of previous techniques such as heat stamp, silk screen, waterslide decals, et al.   Unlike the current rage of 3D part creation, however, to my knowledge there's no home-brew pad printing available at a hoi polloi price for the DIYer.

KD

Thank you for the replies which were very helpful.

On many projects, Sunset/3rd Rail/GGD still uses decals because they create the sharpest lines.  Unlike commercially available decals, these are top slide decals.  In other words, the decal film is on top of the decal leaving only the striping / lettering behind. 

On the diesel projects, screen printing is typically done for large stripes and masking of color regions but it is not quite a sharp as the decals.  On the soon to be shipped Amtrak cars, the stripes as well as letters are decals.