Post by fr8kar on Mar 13, 2017 21:39:33 GMT -5
A couple years ago I posted a Cotton Belt B30-7 that I detailed using the factory painted Atlas HO scale model as a starting point. The prototype cab face features the distinctive L-shaped window used by SP and others, but the model came with a standard cab face. I had a Hi-Tech cab kit that I intended to use to modify the Atlas cab, but after procrastinating awhile I ended up misplacing it.
Another project of mine used an Atlas U33C as a starting point, so I also had an L-window cab to use. I could either cut out the face of the standard cab and replace it with the L-window cab or completely replace the standard cab with all the same details added and modifications made to the L-window cab. I already had most of the parts needed to detail another cab, so I decided to go that direction.
Building a replacement cab left me with a perfectly serviceable SP/SSW cab, but one with a standard front window arrangement. I'm no expert on Southern Pacific or Cotton Belt equipment, so I wasn't sure if I'd find anything that matched the details I'd already added to the cab. After looking through Southern Pacific GE locomotives on Locophotos.com, I ran across some SP B36-7s that more or less were a match for the cab I had on hand (the prototypes only have the sliding windows on the sides, not the gasketed windows at the cab corners).
Recently there was some discussion on the Southern modelers Yahoo discussion group about the wheelbase of four axle Dash 7 diesels as production progressed through the various phases. The HO Sam site linked in the header above gives some good information on this topic. The Trainiax site also provides a tabular breakdown of various phase details and data including the wheelbase here:
trainiax.net/mephase-geb-7.php
What I've gathered from this is that the Atlas models I have (B23-7 and B30-7) match the Phase 1 prototypes with an overall length of 62'-2" and 36'-2" truck centers. The B36-7 - as well as other Phase 3 four axle GEs - have an overall length of 61'-2" and 36'-8" truck centers (I've also seen this as 36'-10"). The length difference appears at the ends of the locomotive where the stepwells are moved 6" closer to the center at each end and the rear truck is closer to the rear pilot than the front truck is to the front pilot. There are other differences including the configuration of the hatches on the left side.
A Mopac C36-7 project left me with a spare C30-7 shell and I already had a couple B23-7 sills on hand for yet another project. This B36-7 was put together from a B23-7 sill shortened at each end next to the stepwells and a C30-7 shell with the clean air room shortened to match the four axle prototype. I made a new hatch for the left side from styrene sheet and rod. Of course the box and brackets for the extra lights were made from styrene using some measurements I came up with after poring over detail photos of the prototype.
Other than that, this was a pretty simple slice-and-dice operation.
I use Model Master enamels for the vast majority of the paint jobs I do. The gray was shot with Euro I Gray, which comes out a shade too light to match the Atlas factory paint. I discovered this a couple years ago when I worked on the B30-7, but apparently discarded that information and made the same mistake again with this model. I have been able to mostly correct the problem by adding some drops of flat black to a quarter bottle of glosscoat and shooting the entire model. The red ends look bad because I used Chrysler engine red instead of Ford engine red. I have yet to correct that but it's a comparatively easy problem to solve.
Here are the two models showing the difference in the shade of gray between the Atlas factory paint on the Cotton Belt B30-7 model and SP B36-7 cab and the Model Master Euro I Gray on the Cotton Belt B30-7 cab and the SP B36-7 body:
And a before and after showing the effectiveness of the tinted glosscoat:
Time to touch up the red and get the decals ready:
The real work is yet to come. I will be creating a new frame for this model since I won't be able to use the Atlas drive under the shortened sill. I've been working on a 3D printed frame to accommodate the different sill length and truck center differences found in the Dash 7 line. It's printed in plastic so it's very light, but I'll be experimenting on ways to power the drive and give it some heft for proper pulling power. I will design it for a Kato motor, Athearn hex driveline and trucks, since the various truck options have been covered well by Athearn or Athearn clone (P2K) trucks. Still waiting on the first revision of the frame to arrive from Shapeways right now, though. Hopefully I'll be able to update this thread with frame photos soon.
Another project of mine used an Atlas U33C as a starting point, so I also had an L-window cab to use. I could either cut out the face of the standard cab and replace it with the L-window cab or completely replace the standard cab with all the same details added and modifications made to the L-window cab. I already had most of the parts needed to detail another cab, so I decided to go that direction.
Building a replacement cab left me with a perfectly serviceable SP/SSW cab, but one with a standard front window arrangement. I'm no expert on Southern Pacific or Cotton Belt equipment, so I wasn't sure if I'd find anything that matched the details I'd already added to the cab. After looking through Southern Pacific GE locomotives on Locophotos.com, I ran across some SP B36-7s that more or less were a match for the cab I had on hand (the prototypes only have the sliding windows on the sides, not the gasketed windows at the cab corners).
Recently there was some discussion on the Southern modelers Yahoo discussion group about the wheelbase of four axle Dash 7 diesels as production progressed through the various phases. The HO Sam site linked in the header above gives some good information on this topic. The Trainiax site also provides a tabular breakdown of various phase details and data including the wheelbase here:
trainiax.net/mephase-geb-7.php
What I've gathered from this is that the Atlas models I have (B23-7 and B30-7) match the Phase 1 prototypes with an overall length of 62'-2" and 36'-2" truck centers. The B36-7 - as well as other Phase 3 four axle GEs - have an overall length of 61'-2" and 36'-8" truck centers (I've also seen this as 36'-10"). The length difference appears at the ends of the locomotive where the stepwells are moved 6" closer to the center at each end and the rear truck is closer to the rear pilot than the front truck is to the front pilot. There are other differences including the configuration of the hatches on the left side.
A Mopac C36-7 project left me with a spare C30-7 shell and I already had a couple B23-7 sills on hand for yet another project. This B36-7 was put together from a B23-7 sill shortened at each end next to the stepwells and a C30-7 shell with the clean air room shortened to match the four axle prototype. I made a new hatch for the left side from styrene sheet and rod. Of course the box and brackets for the extra lights were made from styrene using some measurements I came up with after poring over detail photos of the prototype.
Other than that, this was a pretty simple slice-and-dice operation.
I use Model Master enamels for the vast majority of the paint jobs I do. The gray was shot with Euro I Gray, which comes out a shade too light to match the Atlas factory paint. I discovered this a couple years ago when I worked on the B30-7, but apparently discarded that information and made the same mistake again with this model. I have been able to mostly correct the problem by adding some drops of flat black to a quarter bottle of glosscoat and shooting the entire model. The red ends look bad because I used Chrysler engine red instead of Ford engine red. I have yet to correct that but it's a comparatively easy problem to solve.
Here are the two models showing the difference in the shade of gray between the Atlas factory paint on the Cotton Belt B30-7 model and SP B36-7 cab and the Model Master Euro I Gray on the Cotton Belt B30-7 cab and the SP B36-7 body:
And a before and after showing the effectiveness of the tinted glosscoat:
Time to touch up the red and get the decals ready:
The real work is yet to come. I will be creating a new frame for this model since I won't be able to use the Atlas drive under the shortened sill. I've been working on a 3D printed frame to accommodate the different sill length and truck center differences found in the Dash 7 line. It's printed in plastic so it's very light, but I'll be experimenting on ways to power the drive and give it some heft for proper pulling power. I will design it for a Kato motor, Athearn hex driveline and trucks, since the various truck options have been covered well by Athearn or Athearn clone (P2K) trucks. Still waiting on the first revision of the frame to arrive from Shapeways right now, though. Hopefully I'll be able to update this thread with frame photos soon.
