Briggs Models MLW RS-18 Build Thread

[BCR 570]

Introduction
With my three MLW RS-3s now on Dave Mackinnon's workbench for installation of decoders, lighting and speakers, my attention now turns to replacing and expanding my fleet of MLW RS-18s.  These locomotives were the backbone of the railway's four axle fleet and on the north end could be seen hauling mainline and branchline freights, work trains, or operating as yard switchers.

The Pacific Great Eastern Railway purchased a total of twenty-nine RS-18 locomotives from the Montreal Locomotive Works.  They were ordered in seven batches between 1957 and 1966, resulting in numerous design changes between successive batches.

All twenty-nine units survived into the British Columbia Railway years, and during my chosen era of 1977, were either still in the PGE two tone green with map herald scheme, or the first BCR two tone green with dogwood logogram scheme.  In 1990 BC Rail embarked on a program to rebuild the fleet with Caterpillar engines and they continued to serve the railway until the CN takeover in 2004.


Older Models
Modeling the RS-18s has been a significant challenge; while the ALCO RS-11 models have provided a suitable chassis, a lot of work was required to create an accurate body for the early models.  With their mix of high and low carbody doors, the later models were even more of a challenge.  In 1985 I purchased three Atlas/Kato RS-11s from the first batch to arrive at Pacific N Scale.  They underwent a long conversion process, hampered by novice modelling skills and a lack of suitable parts.  The following in-progress photographs illustrate some of the challenges in modelling the RS-18s, including lowering the short hood, building the cab face, removing the rear battery boxes, and filling the corner notches, changing the carbody filters, aftercooler intake, pilots and fuel tanks, to name a few:






Eventually the models of 607 and 613 reached completion, and have served well on my layout:




While the installation of TCS M4 decoders enabled them to operate on a DCC layout, their tendency to stall when reversing direction was a source of some frustration.  I eventually noticed that the chassis actually shifts slightly when reversing direction, which caused the stalling.  As the process to convert the fleet to sound came along, I realized that these units would not be suitable candidates for conversion, and after seeing the difference in performance between 1985 models with early decoders and 2004+ models with LokSound, my decision to replace them was made.

After numerous operating sessions I also realized that some additional RS-18s would be nice to have, and during the last release of the new Atlas/China ALCO RS-11 model, I acquired four for future conversions.  I have subsequently decided to model a fifth and will attempt to locate another Atlas/China RS-11 from the last run when possible.  I have not attempted to build five locomotives at once before, but a batch build makes sense to me, so here we go.  I will also be assisting friend David Morgan with his build of PGE 590 in the original orange and green Caribou herald scheme.


The Prototypes
I wanted to select prototype units which were known to have operated in the north during 1977, units which represented the variety within the fleet to some degree, and units in different paint schemes.  Thanks to friend Ross Pugsley who lived in Fort St. John and took many photographs of the railway during my time period, I have some nice reference photographs to work from.

BCR 602 represents the first four units which were delivered as high short hood, long hood forward.  (All subsequent units were delivered as low short hood forward.)  In 1977 601-604 were still with high short hoods and were operating up north.  602 had been repainted into the BCR scheme and is pictured here at Fort St. John in 1977:




PGE 607 will be a direct replacement for my older model.  It belongs to the first batch of low short hood units.  It remained in the PGE map scheme well into 1978 and in addition to working on the Fort St. John Subdivision was also photographed on the Dawson Creek Subdivision:




BCR 613 will be another direct replacement for an older model.  It is from the second batch of low short hood units and has a different dynamic brake grid arrangement on top.  Like 607 it has the earlier style carbody with even height doors, and the earlier 1200 gallon rectangular fuel tank.  In 1977 it had been repainted into the BCR dogwood scheme.  I also wanted this engine because it served as helper during the Provincial Museum Train's visit to the north end in 1975.  It is seen here departing Fort St. John in 1977:




BCR 617 sports the later style of carbody with a mix of high and low doors, and a revised filter arrangement.  It also carries the later 1600 gallon fuel tank with angled sides.  It was photographed on the Fort St. John and Dawson Creek Subdivisions during 1976-1978.  In this 1978 photograph it still sports the original pilots with MU retainers:




PGE 628 belongs to the last three units delivered; these were distinguished by their winged snow plows similar to those seen on the C-630Ms, M-630s and M-630Ws.  628 was one of the last RS-18s to wear the PGE map scheme, seen here still holding out in November 1979:




New Models
As mentioned, my new models will be based on the most recent run of the Atlas/China ALCO RS-11, which provides the correct length chassis and correct trucks:




This exploded view shows the carbody, deck/sill assembly, and the mechanism.  The carbodies will be discarded entirely, the deck/sill assemblies will be rebuilt with new pilots, steps and handrails, and the mechanisms will be modified for the new fuel tanks, short hoods, and DC equipment:




Briggs Models has progressed from offering various cast resin parts for RS-18 conversions, to full cast resin carbodies and parts, and now to 3D printed carbodies and parts.  These parts are produced on the photon printer and are the closest to injection-molded models I have seen, so are definitely worth the upgrade from the former cast resin parts.  These are the parts for the cabs and short hoods:




These are the parts for the long hoods, with the two early style on the left and the two later style on the right:




These are the parts for the fuel tanks, with the two early 1200 gallon tanks on the left, and the later 1600 gallon tanks on the right, all with air tanks:




This collection of parts includes pilots, steps, strikers, battery boxes, lights, and more:




I prefer to work from the wheels up when building locomotives, so the first step will be to modify the mechanism for the new fuel tanks and the short hoods.


Tim

[mandealco]

Great post Tim, this will be a fun project.  Looking forward to the updates.
Cheers
Steve

[BCR 570]

Thanks Steve; will be fun once I get all the pilots sanded off - not looking forward to that for five units.

The Mechanism
The latest iteration of the Atlas/China ALCO RS-11 runs very well, and provides us with the correct trucks and distance between truck centres.  The chassis is stamped 2006 and is advertised as "decoder ready" with a lighting board on top which can be readily changed out for a decoder such as the TCS AMD4.  Unfortunately, this model comes with a colossal fuel tank which will have to be replaced:




The fuel tank is easily removed from the chassis, allowing us to see how much metal is inside the fuel tank.  Note that this portion of the chassis, while fortunately beneath the motor, retains the contact strips collecting power from the trucks and transferring it to the chassis halves.  A portion of this metal inside the fuel tank, specifically that holding the contact strips, must be removed in order to fit a prototypically-sized fuel tank:




While a milling machine would work for this job, the metal is fairly soft and can be milled  by hand with a large flat file if necessary.  This work is best accomplished with the frame halves held in a vise.  Prior to undertaking the work it is best to remove the entire drive train and trucks, and then reassemble the empty frame halves.  After milling and reassembly, the underside of the mechanism looks like this:




Note that the contact strips and the metal portions of the chassis retaining them are now gone, but the Briggs Models 1200 gallon rectangular fuel tank will now fit snugly onto the mechanism.  I foresee a problem with the later style 1600 gallon angled tank as it is approximately 33 scale inches shorter and will not fit without the removal of more metal.  The next photograph shows the modified mechanism with 1200 gallon fuel tank in place:




For the model to run, the pick-up from the trucks to the chassis halves must now be replaced somehow.  Jeff's solution was to attach tiny super-flexible wires to the pick-up tabs on the trucks, run the wires up between the frame halves, and attach them to either side of a piece of styrene to provide the required insulation from each other.  The styrene board will likely be replaced with something a little more substantial when we come to the DCC conversion process, but for now this method of pick-up works very well.  We have seen Atlas adopt this method with the latest version of their C-630, and I suspect that when a future run of the RS-11 comes with DCC and sound, it may well have factory wire pick-up.  When installed the pick-up wires and the styrene insulator plate are hard to see:




For four of my units, the mechanism must also be milled at the front end to accommodate the low short hood.  The height of the chassis is lower than one might expect for a high hood unit due to the need to accommodate the large LED for the headlight.  This means that the front of the mechanism needs to be lowered by only about .040" in height.  Again, removal of the drive train is recommended to avoid contamination with metal filings.  In this comparison photograph, the model on the left is un-modified, while the model on the right has had the front end lowered to accommodate the new short hood:




After modifications to the mechanism and conversion to wire pick-up, we want to be sure that the model still retains its excellent running characteristics.  Prototypically accurate models are great to look at, but we want them to be able to operate well too.  The following video shows David Morgan's mechanism running with replacement fuel tank after the conversion.  It was filmed running in DC mode with an old Tech II power pack.  This set up will be used to run in the mechanisms, after which their operation should improve even further:

Now that this conversion has been proven and the new 3D printed fuel tanks checked for fit, my next step is to get the remaining mechanisms milled and converted, and all of the fuel tanks assembled.  I also need to determine how to fit the later style fuel tank.


Tim

[BCR 570]

New Fuel Tanks  (Part 1)
With the chassis modifications and initial fuel tank fit worked out, I can now move forward on assembling all of the required fuel tanks from the Briggs kits.  These are essentially pre-production parts as I am testing them out and reporting back to Jeff with any required modifications.

The early PGE/BCR RS-18s (601-613) carried a 1200 Imperial gallon fuel tank which was rectangular in shape.  It was identical to that used on the earlier RS-10s and the later RS-3s.  The later PGE/BCR RS-18s (614-630) carried a 1600 Imperial gallon tank which was shorter but wider with angled sides.  Jeff offers both styles as 3D printed kits, which includes fuel filler pipes and air reservoirs. 

This photograph shows the parts for the 1200 gallon tank (body and bottom) prior to assembly:




This photograph shows the parts for the 1600 gallon tank (two halves) prior to assembly:




With both tanks, the air reservoirs plug onto locating ridges printed onto the tank sides.  After inserting the bottom plates on the rectangular tanks and joining the two halves of the angled tanks, the assembled tanks look like this:




I need to obtain one more rectangular tank for 602.


My attention now turns to the pilots, commencing with removal of the molded pilots from the sill assemblies.  Lots of sanding!


Tim

[BCR 570]

Deck/Sill Assemblies (Part 1)
With the fuel tanks built it is now time to move up to the deck/sill assemblies.  The MLW RS-18s had different pilots than the ALCO RS-11s, and after the first four PGE/BCR units the steps were also different.  For 602 I will need to remove the pilots from the RS-11 deck/sill assembly; for the other four units I will need to remove the pilots and the steps.  Jeff has created parts for both pilots without steps and pilots with steps, which will need to be adjusted once I have some pilots removed and we are able to undertake some test fitting.  Jeff is also working on an etched handrail set  which will mate with the deck/sill assembly.

In removing the pilots, the goal is to end up with a perfectly flat and square mounting surface for the replacement parts.  With my previous MLW RS-3 project I determined that cutting off the pilots with a razor saw was a little risky in terms of achieving the desired result.  I ended up fashioning a jig out of styrene to hold the deck/sill assemblies perfectly level and square, and then using my True Sander to remove the pilots.  While this process was longer and harder on the hands, the results were exactly what I was hoping for.  In creating the jig for the RS-18 decks, I made it a little larger so that it was easier hold onto and thus easier to keep aligned on the True Sander:




The deck/sill assemblies press into the jig for a nice tight fit and are held perfectly level and square to the sides of the jig:




After cutting off the footboards with side cutters, the jig with the part installed is then held against the guide on the True Sander and the long sanding process begins:




Slow and steady wins the race here.  As much as I want this task behind me, going slowly and ensuring straight, even strokes with the sanding block yields better results.  It is also necessary to stop occasionally to blow away the styrene dust and de-clog the sandpaper.  I also stop regularly to check the alignment across the pilot with a machinist's square:




and also the alignment from top to bottm:




Eventually the stage is reached where what is left of the pilot face breaks away from the steps.   At that point I switch to a finer grade of sandpaper to clean up the mounting surface.  WIth the pilot removed, the end of the deck/sill assembly now looks like this:




I have now removed all pilots from the four decks on hand.  The next step will be to remove the steps but that will wait until after my next meeting with Jeff on Saturday, when we can review the intended fit of his parts.  I will have two more pilots to remove when my fifth RS-11 arrives.  Until then, my attention will turn next to the carbody parts.


Tim

[BCR 570]

Deck/Sill Assemblies  (Part 2)
This project has taken several steps forward during the last several days.  My recent acquisition of a fifth undecorated Atlas ALCO RS-11 arrived last week, enabling me to disassemble it and complete the removal of pilots for all five units.  This process went very well and I am very happy with the results.  Here are the five deck/sill assemblies after removal of all pilots from both ends:




Last weekend I met up with Jeff Briggs to show him the results of the pilot removals and provide him with an opportunity to take measurements for revising his parts to fit well.  The high hood unit will receive new pilots without steps, and the four low hood units will receive new pilots with steps.  This photograph shows a modified deck/sill assembly with pre-production parts for both types of pilots:




The various pilots will incorporate further variations among them, with earlier units having slotted striker plates beneath the couplers and later units having solid striker plates, and the original pilots with MU retainers for 590 and 617 vs. modified versions with MU retainers removed for the others.

Further work on the deck/sill assemblies will now wait until Jeff has refined the parts and printed new ones for testing.


New Fuel Tanks  (Part 2)
I have been concerned about how to fit the later style of fuel tank which is shorter than the earlier version.  As I suspected, it is not possible to remove the portion of the mechanism which would be left exposed ahead of the later fuel tank.  This photograph illustrates the underside of an RS-11 mechanism modified to accept the early fuel tank, with an early style tank on the left and a later style tank on the right:




In this photograph it is possible to see the two issues with attempting to remove the metal ahead of the later tank.  This area includes a somewhat tenuous connection to the rest of the chassis, and it includes a black plastic portion of the motor mount:




Sometimes one has to compromise, and I wished to explore a possible solution whereby a centre portion of the front wall of the later fuel tank was removed in order for it to fit over the modified mechanism.  I used an Xacto razor saw to cut out the front wall of the tank, leaving the angled extensions on either side intact.  On the left is the later tank as originally assembled; on the right is a tank with the front wall opened up:




These views shows the early style rectangular tank fitted to the modified mechanism:




In this side view, we can see that the early style tank is centred correctly between the front and rear trucks:




This view of the underside of the mechanism with modified later style tank fitted shows the front portion of the mechanism protruding through the front of the fuel tank:




In this view from the side we can see the fuel tank oriented correctly toward the rear truck.  On the prototype, the area between the fuel tank and the front truck is open; in this photo we can see the portion of the mechanism left exposed ahead of the later style fuel tank:




This oblique view approximates what would likely be a more normal viewing angle for the models when in service.  The angled sides of the tank remain intact, capturing the look of the later tank, and the exposed portion of the mechanism ahead of the tank is a little less noticeable.  I am hoping that when painted black and it is underneath the deck it will be a lot less noticeable.  We'll see:




I also wish to explore the possibility of covering the exposed portion of the mechanism with .010" sheet styrene for a cleaner look.  This would be painted black, thus avoiding having to paint the portion of the mechanism.

Time to move on to the carbodies!


Tim

[philippe.whyte]

Hi Tim,

This is excellent work!  I feel very fortunate to have you spending so much time and effort getting these details right as I will have a direct benefit when the time comes for me to build mine (and I'm sure for many other BCR modellers also).

Philippe

[BCR 570]

Update - New Parts
This project has been on hold for a while awaiting some new parts.  Part of this project is working with Jeff to test out parts, make recommendations, and then test revised parts once they are ready.

First up is a revised late style 1600 gallon tank, which now comes with the opening in the front wall to accommodate the portion of the chassis which cannot be removed (see earlier post).  Pictured below left is a part straight out of the printer, and on the right is a de-sprued part showing the front opening:




Next up are revised parts for the early style pilots without steps below left, and on the right are later style parts with steps:




After receiving the parts for the various cabs and shells, I realized that BCR 613 is actually a hybrid carbody of sorts with early style carbody doors and filters, but with later style dynamic brake grid.  Fortunately the 3D rendering and printing process allows for quick changes and Jeff was able to print for me a correct long hood for 613:




I also received the cab and hoods for BCR 602 which was still a high hood unit in 1977:






With these two new hoods now on hand, my planned fleet of five RS-18s will now look something like this - from L to R are 602, 607, 613, 617 and 628:






Jeff has prepared frets for the RS-18 handrails and other detail parts.  This is the early version for 601-604 with deck-mounted handrail stanchions:




And this is the late version for 605-630 with the sill mounted handrail stanchions:




And finally, friend Philippe Whyte has prepared for me a nice set of decals for the five RS-18s including striping, cab logograms and numbers, and number boards:




I now have everything on hand to continue with this project.  All I need now are some free evenings . . . 


Tim

[BCR 570]

Update - New Parts
Sometimes you have to take a step or two back in order to move forward.  This project is very much about working with Jeff to refine his RS-18 parts for others to use, and this build therefore has involved a considerable amount of testing, discussion, and reprinting.

It became apparent to me that fitting the revised pilots with steps onto the Atlas/China decks was going to be a difficult task as it meant cutting a notch out of the deck to correct the profile of the deck above the steps.  This involved obtaining a precise fit between the Delrin deck and the resin pilot/step assembly.  It became obvious to both of us that the skill level required for this process was higher than desired for assembly of these parts.

At this time Jeff was preparing parts for release of new ALCO RS-27 and RS-36 kits which had similar decks, and suggested printing some RS-18 decks with steps incorporated, to which the correct pilots could be added.  Those parts were printed along with revised pilots, battery boxes, and pilot accessories:




Unfortunately, after some evaluation, it was determined that these parts were not going to work.  There was inherent warpage in the decks, and there was difficulty in getting them off the sprues intact.  Jeff subsequently revised the decks for the RS-27 and RS-36 kits to include integral deck and hood parts.  (These can be seen on his website at www.briggsmodels.ca.  They are proving to be much better in terms of print quality and straightness.  Accordingly I have asked Jeff to print similar parts for my RS-18s, with the aim of eventually phasing out his existing line of RS-18 parts in favour of integral deck/hood parts.

Parts for the MLW RS-10s will also be available, and I was recently able to acquire two additional Atlas RS-11 units from hte most recent run for my replacement RS-10s.  I may elect to build them at the same time.

I will be back with photographs of the new shells when they arrive, and I can then finally get back to work on these.  Given the new direction in which these are going, I will likely tie off this build thread and start a new one.


Tim

[BCR 570]

New Direction
A big bag of RS-10 and RS-18 parts arrived last weekend:




As mentioned earlier, after successful release of his RS-27 and RS-36 kits with integrated decks and bodies, Jeff proposed going this route with the RS-10s and RS-18s.  He has also acquired a new resin which preserves the fine detail yet is more resistant to shattering during de-spruing.

These photographs show a reject shell which is actually an RS-10 long hood and RS-18 short hood, but it illustrates the results:






These new models have the correct steps and the pilots plug on to the ends, so no more cutting of frames, etc.  These parts are also designed to accept the etchings for the handrails seen earlier in this thread.

I have to say that these photographs do not do the parts justice as they are hard to photograph in grey.  They do not look too far off a commercial injection-molded part to my eye.


These new parts render much of this thread irrelevant so I will sign off and start a new one, which will also cover my planned RS-10 rebuilds.

Tim

[paggs]

Great thread Tim,  looks like you're keeping Dave busy. Let me know if you are still looking for RS-11s

Mike Pagano

[central.vermont]

Boy this has been a great thread to follow Tim, your doing awesome work my friend!!

Was wondering why don't you mill the section of frame that sticks out from the fuel tank?
I know the motor cradle tabs are there but you could mill up to that and have it be less noticeable.
 Just a thought.

Jon

[BCR 570]

Thank you - if you are talking about those flat extensions above the fuel tank, those serve to support the deck at the right height, and are hidden by the deck and side sills.  One has to be very careful removing material around the motor area so as not to weaken the frame.

Tim

[central.vermont]

Thank you - if you are talking about those flat extensions above the fuel tank, those serve to support the deck at the right height, and are hidden by the deck and side sills.  One has to be very careful removing material around the motor area so as not to weaken the frame.

Tim

No I'm actually talking about the piece of frame that hangs down ahead of the tank that you can see.




I realize the thin piece that protrudes from the top above the tank is for the sill to rest on.
Jon

[BCR 570]

Ah, yes.  That piece cannot be removed as it would sever the frame halves.

Tim