ATSF GP7u

[faraway]

I did see some brass GP7u from Hallmark during my recent trip in Denver and Dallas.
The brass model has been made by "Samhongsa" in Korea. Hallmark was the US importer located in Dallas. The dealer told me Hallmark is out of business for at least 10 years. The model is "somewhat" antique.

Most of the engines were incomplete and the "sound" was horrible at best. However one engine in Dallas looked good and I got it knowing I had to do some (serious?) rework on the drive at home.

Adding a DCC decoder was easy but the test run showed to key problems
- noise all over the engine
- pickup only on two wheels per truck. The engine stuck passing DCC booster border lines

The motor is not that bad but the trucks are made of "iron" and have only pickup on one side. Replacing the trucks is not easy because the mounting is very different and the hight of the mount and the motor drive shaft differs greatly from todays standards. That looked very complicated...

I got a much easier way to do it.
Take a standard P2K ATSF GP7/9 and replace only the short/long hood and the cab. The brass parts are glued in place. The complete drive is untouched. Only the weight had to be removed because the brass hoods are to narrow. However the brass parts added sufficient weight for my small layout. Minor adjustments in the P2K shell around the cab are easy to do.

The new parts need weathering and lamps are on order to be installed. The Hallmark engines had only front lamps.

It is a real hybrid of brass and plastic now. That does not worry me. I wanted a GP7u ready for work on the layout and got it

[faraway]

The lamps have been added with a method I did use the first time.

Glue two 1" long fiber-optics in the distance as the lamp hole are in the shell to the end of a LED of your choice. You might sand the shape of the LED end to better fit the fiber-optics. The glue to be used might be a problem. I did use a German industry glue that of the brand name "Schwanheimer Industriekleber" with the filler. Standard CA glue might fail to bond fiber-optics and LED housing with the necessary strength.
The assembly gets a silver paint for better reflection and the LED two wires. Next simply plug the fiber-optics into the lamp holes of the shell, cut the fiber-optics flush and connect the wires (don't forget a series resistor) to your DCC decoder.

Very easy to do and a perfect replacement for one or two micro 1.5 Volt bulbs used in so many models. The current drawn by the LED shall be much lower than the old bulbs. It is a "cool" assembly.

Next step is weathering to match the P2K and Hallmark paint better. I brought "Higgins Black India Ink" with me from the US. That will be the base for the wash.

ps. My standard CA glue had problems to handle the P2K plastic and the brass. I did use the industry glue also to strengthen the shell connection too.

[Green_Elite_Cab]

I'm kinda surprised you didn't already have one of these units. Even though I model on the east coast, the GP7Us have caught my eyes. I remember helping someone plan on how to kitbash one once, but I'm not sure he ever did it.

Anyways, awesome model!

I too would like to use fiber optics in my models, but i'm unclear as to exactly how you hook them in to the LEDs. Do you have pictures of this?

[faraway]

...I too would like to use fiber optics in my models, but i'm unclear as to exactly how you hook them in to the LEDs. Do you have pictures of this?

The LED with the fibers was to small for useful photos.
I put paper on the table, put the LED on the paper and aligned the fibers to the front of the LED. Next came several layers of industry CA glue and filler (a white powder). Each layer was ready within 30 seconds. The outcome looked awful like a nugget but it is later not visible and works. That "nugget" has a bottom of paper. Do not forget the paper or you have to fit the desk in the shell

The modern LED are so powerful that even a lousy optical connection is no a real problem.

Schwanheimer has web page in English language. That might be helpful.
That is the glue: http://www.schwanheimer-industriekleber....sives.html
and the filler: http://www.schwanheimer-industriekleber....iller.html

[doctorwayne]

I don't use lighting in my locos, but many LEDs can be "shaped" somewhat using files or other methods. It may be possible to drill the tip of of the LED slightly, then insert the end of the fibre optic strand into the hole. With such a mechanical joint, regular ca may hold it in place.

Wayne

[Green_Elite_Cab]

I don't use lighting in my locos, but many LEDs can be "shaped" somewhat using files or other methods. It may be possible to drill the tip of of the LED slightly, then insert the end of the fibre optic strand into the hole. With such a mechanical joint, regular ca may hold it in place.

Wayne

This is what I initially thought, and so I promptly drilled a hole down the center of an LED long enough to let a short length of Fiber optic be relatively secure. Unfortuneately, this "fogged" the LED around the hole. The light was not nearly as bright as if i had just held the LED to the surface. If there is a way to polish it clear, this method would probably be prefered.

[doctorwayne]

This is what I initially thought, and so I promptly drilled a hole down the center of an LED long enough to let a short length of Fiber optic be relatively secure. Unfortuneately, this "fogged" the LED around the hole. The light was not nearly as bright as if i had just held the LED to the surface. If there is a way to polish it clear, this method would probably be prefered.

Did you use a pin vise or a powered drill? If the latter, it may have melted the LED slightly, causing the fogging. In either case, try using the same bit in a pin vise, but turn it counterclockwise to polish the already-drilled hole.

Wayne

[rrinker]

Same subject just came up on that 'other' forum.

If you have a clear-cased LED, hold it up to the light. You can see all the important bits inside, including a hair-thin wire leading from the smaller terminal to the top of the larger one. At that joint is where the actual diode action takes place. You can turn, drill, sand, file, etc. an LED so long as you don't go so far as to disturb any of those bits. One place people mess up is turning the lower sides near the terminals - if the case gets too thin there it will allow the legs to flex, which will break that delicate joint inside. When drilling in from the end, that wire sticks up a bit above the larger bits of metal inside, so don't drill down too far.

--Randy

[faraway]

Drilling a hole to mount one fiber optic is a good choice. Most engines I have are equipped with two front/rear lamps. I want/wanted to illuminate both with one LED powering two short fibers. To get that done I grind a notch on both sides and glued the fibers on the step. To get that more perfect the fiber should have a corresponding notch (didn't do that but will do next time).
I know professional fiber optic connections are polished when the fiber has to be cut.

[faraway]

And finally the engine is detailed with ditch lights, MU cable and got lettered to match the age after 2000. The road number chosen is a GP7u without dynamic breaks, front lamp in the cab and has been at least been ones in the SoCal area (photo 2003, Commerce). The placement of antenna, horn and air condition does not match any prototype I could find photos of. However, because that part is brass and not likely to be rearranged easy it has been left untouched.

The engine is doing the small yard and the local industry together with a GP30u (2447, currently assigned to LAJ).

[Russ Bellinis]

Just for the information of anyone who might want to build a Gp7u from a model Gp7 equipped with dynamic brakes, the Santa Fe had a lot of those too. The dynamics were disconnected and the grilles for the resistor banks were plated over. I think the dynamic brake fan was removed, and the hole covered with a plate.

Nice looking loco Reinhard! It is amazing that the colors match so well between the old Hallmark and the new P2k model! I have seen so many variations on the yellow color of the S.F. blue & yellow warbonnet freight scheme that I seldom see models from two different manufacturers that match.

[faraway]

A set of short-, long hood and cab has been left from the the GP7u kit bashing based on the Hallmark brass unit. Another P2K Santa Fe P2K was on the shelf too.
It was a natural wish to have another GP7u made of that residual components. I am been afraid to do the complicate GP7u cab but I found out a small series kept the original round roof on the cab. The Santa Fe 1311 had dynamic brakes, the front light in the nose, the simpler round roof and made it as the 3821 into the BNSF area. I have to ignore two differences
a. the Santa Fe 1311 has been used as a slug mother doing switching in the Chicago area
b. the BNSF 3821 could be found on photos taken after 2003 with brand new BNSF colors only.
However, I "assume" the 3821 has been BNSF patched with it's original Santa Fe colors prior to 2003.

You are very welcome if you know another BNSF GP7u with dynamic brake bulbs (they are plated over), lamp in the nose, round roof and still in Santa Fe colors with BNSF patch (and might be used in the LA area after 2000).

There is a nice introduction with photos how to do the conversion with the angeled roof. I did use that for the low hood. The new front of the cab was a problem. I have not been to optimistic to get it well from a piece of styrene and the number boards with a frame are another open topic. I solved it by using the parts of the cab of a spare Athearn CF-7 2563 shell.

Currently is the number board unit and the cab front wall waiting for the glue to set. The low hood is only put but not glued in place now.

I want to avoid to do much putty and sanding but to keep the original yellow paint as is where ever possible and to the paint job with a brush only. That is the reason why I did not follow the directions and did not sand the fireman's side of the low hood totally flat. The old number boards have been closed with the unused parts from the low hood to get the yellow color. The Athearn CF-7 window wall color fits the P2K yellow very well.

[faraway]

That's it for today.
I do not recommend to paint with a brush only. I should have used my airbrush. The class lights had to be removed to. Together with the old number boards was a layer of putty and some sanding required. The yellow paint (Polly Scale Reading Yellow) could not cover gray putty on yellow background. An extra layer of light gray undercoat was necessary. Yellow required four other layers. That is far to much to look good....

The footsteps have been removed and the blower on top of the dummy dynamic brakes has been replaced with two stacks.

The decals will need to set over night until I can continue with more details.

Update: Last task was to paint the top of the short hood blue. The blue color worked well but the masking tape failed... what a mess :evil:

[faraway]

Ok, ready for the late shift switch job

[faraway]

I am doing another GP7u but this time with a so called angled roof (Topeka Cab). I am a fan of shopped noses even that might stretch my timeframe of 2005 one or two years into the past...
(I think the term "Topeka Cab" is misleading because the Geep conversion has been made in the Cleburne, TX shops after the CF7 series was over and not in the Topeka, KS shops)

Base is an Proto 2000 Santa Fe GP7. The cab is a modified (shortened) Athearn RTR CF7 cab. Unfortunately are the side window a bit off the center with that method but it ensure a good roof shape.




Next is no number boards in the nose, no head lights in the cab and no dynamic breaks at all. A friendly CF7 donated a roof with stacks and the correct radius at the sides.



Plan change, I will do the 1356. That moves the headlight back to the cab and get a clean nose when the putty has set. the foot boards etc. have been replaced by plain plates.