It would be helpful if you

It would be helpful if you could post a picture of the wall you're working on. I use a modified version of method #2: paint the wall with the brick color(s), fill the mortar lines with a mix of plaster of paris and tempera paint, then carefully spray the whole thing with water. If the wood is completely sealed this will not do any damage and the remaining plaster can be wiped off with a damp cloth. I even use this method with brick made of cardboard. Here's an example (N scale):

Try using Powders

This is a in progress photo from earlier this year. The brick is from Monster Model works. I colored the brick with several washes of Dr Bens rusty reds and brown powders with a light overwash of white. I thin the powders with 91% alcohol and apply with a soft brush. Depending on your prototype you can use thinned powders to apply the grout lines. Note that the powders have some build up in the grout lines which provides a nice texture. On this prototype the grout lines are more the same color as the brick so I did not apply any additional colors. I have since gone back and repainted the belt rail to blend in better. The belt line brick is the very thin laser paper that Jimmy sells. Initially it did not take the powder paint as well as the wood brick. One note: be sure and brace the wood brick adequately to avoid warpage and do not apply heavy coats of the powder/alcohol mix. I paint more and more of my structures using the powder painting method.

I didn't really concern

I didn't really concern myself with the mortar lines being mortar color ! On both these laser cut stations, I sprayed the walls my brick color, then went over them liberally with a stiff brass wire brush. I just kept scrubbing the surface to expose the underlying wood color to varying degrees. Maybe not perfect, but I was pleased with the results ....

Mark.

image of the model

Here is the model on a store page

http://www.amherstrail-store.org/product-p/ars_station.htm

The station was built in 1853, the brick is colored, well, a solid brick red.  The mortar lines are thin like in older structures.  The corners are not brown - it is laser burns and I guess for the sales image they did not do much other than plunk it together.

I had not considered the red paint filling in the lines.  I think i will try a grey wash, then dry brush with red.

The whole thing is an even color, the large roof overhang has prevented significant weathering.  Thank you for the warning about warping

Monster Modelworks How To...

Nice Job Ernie...

This is Jimmy from Monster Modelworks.

Here is a link to the current vendor selling our products.

https://www.larkspurlaserart.com/monster-modelworks-products

Thanks

Jimmy

Try Looking at ITLA

You may want to log into the ITLA website. They have tutorials on painting their products. ITLA makes wood panels that are engraved brick. The web site tutorials include how to color the brick and mortar lines.

coloring wood "brick" panels

I'd first suggest going to youtube.com and searching for "Jason Jensen" Jason has done a large number of excellent videos demonstrating a wide variety of step by step painting and weathering on his very realistic and dtailed award winning HO scale structures including painting wood brick walls. Jason uses very simple hand painting techniques that anyone can follow and use. HIGHLY recommended!

On my own N scale wood "brick" walls I use a light application of cheap big box brand rattle can flat red oxide automotive primer as a seal coat/base color, applied to both sides of the wall to prevent warping, and to waterproof the panel. You could instead choose a flat light tan or brown cammoflage paint or whatever base color you want your brick. After the spray has dried, I then apply several colors and shades of paint with a sponge dipped in thinned acrylic paint and rubbed nearly dry on a paper towel, then dabbing the brick surface in a random pattern, don't try to cover completely. Finally I pick out individual bricks with a "dry brush" small paint brush of different colors. The more variety of subtle color variations you apply the more realistic the brick will look. Finally once I'm satisfied with the wall appearance after it has dried, I rub the surface with talcum powder to color the grout lines. Wipe the surface of the brick with a slightly dampened paper towel to remove the talcum from the brick surface. I may leave some to a lot on the brick to show age since old mortar tends to bleed white onto the brick. Once that has dried for a couple hours I lightly mist with flat clear spray to seal. After the seal coat has dried, I apply weathering powders and another coat of flat clear.

Mortar lines in 1853 buildings

As John Nehrich correctly pointed out, many brick buildings in the second half of the Nineteenth Century had almost invisible mortar lines.  The base color of the brick tended to be a dark, bluish red like Tuscan, the trim was often red terra cotta, and dark mortar made the lines almost invisible.  Mark R.’s first station above is a perfect example of this. Visible mortar lines would be a mistake. 
 

Buildings like this are common in Pennsylvania, New York State, and industrial cities in Massachusetts and Rhode Island.  British modelers in the Midlands have only to walk out the door and find dozens of local examples. 
 

TLDR:  visible mortar lines aren’t always prototypical.  
 

The problem we always get

The problem we always get into when talking about motor joints is scale and proportions.

In a real brick you get about a 1/4 to 3/8 joint with the brick making up the rest of the 8” width.  Or about 1/32 to 3/64 of the width.  Looking vertically you get three bricks and three mortar joints (same size as above) in 8”. Or about a total of 3/4” to 1 1/8”   Or about 1/9 to about 1/7th of the total.

The best bricks in plastic in HO scale has way to big of mortar joints as such any color you use in them is over emphasized.  And changes the way we perceive the wall color.  Laser cit walls are a bit better and obviously I have not examined them all. So some may be better then others.  
Also usually when we put on the the mortar it does not get completely whipped off so slightly tints the brick as well.

I have always considered that it may be a good idea to slightly tint the mortar with the brick color to thus make the wall look more brick colored then mortar colored.

Try standing far enough away from a brick building to that it takes up as little percent of you view as a model building does and you probably are far enough away to not see the motor joints.  The same way that at that distance you don’t see nail holes.

Once again some things don’t scale properly 

Doug M

Stations

Mark, you mention these 2 stations were laser cut. What scale, and were they kits? If so, whose kits? BTW, they're gorgeous, especially that long one!