Tuesday, April 24, 2012

Upgrading Bachmann BR Mk 1 Suburban Coaches

by John Kendall

24 April 2012

These coaches are generally very good. Body mouldings are crisp and decoration is top notch. I have two lots of these: 4 in crimson and 4 in lined maroon. The latter batch came out last year and have improved decoration in the form of window transfers and overhead warning flashes. By the way, by using a magnifying glass, I determined that the blue sign on the window of the brake coach compartment adjacent to the lav. says "LADIES ONLY".

However, being a couple of generations old, the coaches are sorely lacking in two significant areas:

1) Glazing - definitely NOT flush and
2) Undeframes - very clunky and crude

This project will be in two parts broken down into the categories above.

I will first of all add flush glazing from 2 sources. The first will be the Extreme Etching laser cut flush glazing from Shawplan. I have never seen a review of these so I think one is overdue. The second source will be SE Finecast flush glazing. I used this for my ex LMS suburbans - see post below.

The next phase will be to rework the underframes. For this I will use components from Comet Models.

I have eight coaches to do (groan!). The Shawplan glazing pack can be seen on the left. Next to it is a pack of underframe components including vacuum cylinders, battery boxes, dynamos and assorted other bits. The next pack contains switch boxes and oil valves. Finally there is a pack of buffers and jumper cables.

I've been working on the flush glazing and here is the result:

The brake on the left has flush glazing (in case you didn't know).

The underframe is held on with quite sturdy clips. The best way to get it out is to lever the coach side away from the underframe using an Xacto blade and pry the other side with another Xacto. The lower step is quite fragile so be careful (ask me how I know).

First, to use the Shawplan glazing you must REALLY want to flush glaze your coaches. It is very fiddly. I got off to a bit of a rough start but with practice I got in my stride. There are NO instructions and the best I could do was find some photos on the Shawplan site/blog.

First question: what to use for adhesive? I opted for Future (old). I understand that there is a new formulation which is not as good for this job (I imagine it does polish floors though).

The pack contains door windows and compartment windows. Remove only those windows you want to install from the fret. I used a sanding stick (nail file) to smooth the corners. I decided to begin with the door windows. The windows go in from the front and you need to understand that there is a very subtle taper which means you need to be careful that the window goes in the right way up. For the door windows there is also, again, a very subtle difference in corner radius delineating top and bottom. Get it wrong and there will be a gap at the bottom.

I used a small flat brush to apply the Future very carefully to minimise getting the stuff on the coach side. When not in use, put the brush in a container of water. Do about half a dozen at a time and allow to dry for about 15 minutes. Check that the windows are still where you want them. Any that are out of line will be obvious when viewing along the length of the coach.

I have done a second open and found that the compartment windows don't seem to fit as well as on the brake. I put this down to tiny differences in window opening dimensions. Running a curved Xacto blade along the inside of the windows will help to open them up. Yo may want to fettle the windows a bit as well, particularly the corners.

25 April 2012

Since I had the coaches apart and the windows are much clearer than the old ones, I decided to improve the interiors somewhat. Nothing fancy but just painting floors and seats. I'm not entirely sure and I did do a search but I think 2nd/3rd class seats were red. The simple representation of compartment pictures is taken from a Bill Bedford seat download, free on his site: http://www.mousa.biz/downloads/coach_seats.html

The coaches look brilliant to me as evidenced by this picture:

I added security bars on the parcels compartment window of the 2 brakes by:

1) chemically blackening 0.020" and
2) gluing it into place

I still need to add "No Smoking" decals.

That's phase 1 a) done. Phase 1 b) will add Finecast flush glazing to 4 other coaches.

2 May 2012

I completed Phase 1 b) today.

The effect is good although perhaps not as crisp as the Shawplan. Finecast glazing is vacuum formed, a technology quite a few years old. I am pleased though.

The windows come as two sheets, one for door windows and one for compartment windows. I cut them out with scissors. These go in from the back and most of the time they just pop in, held firmly enough to do the whole coach.

In many cases, the windows wouldn't go in and for these I resorted to a curved Xacto blade to scrape the window openings and to carve the corner radii. Do a little at a time and keep trying your window until it goes in. The sheet does include windows of varying sizes. Some of the door windows wouldn't stay put so I had to glue (Future floor polish, aka Kleer) these one at a time. One advantage is that the Future can be applied to the backs of the windows reducing the risk of getting it all over the coach sides. I used a Qtip to mop up excess Future from the windows.

As a final touch, I used Modelmaster "No Smoking" transfers.
Now to start on Phase 2. The components I will be working with are shown:

At the top is the Bachmann underframe and below that are the Comet components. The Jumper Cables and Buffers are really part of the body. I will have to think about whether I use the buffers, the Bachmann ones are not bad.

7 May 2012

I got two proof of concept underframes done over the last week. One is the Comet U/F pretty much out of the packet. The other is a hybrid using Comet components but the Bachmann plastic U/F with a great hole in the middle.

Here are the results:

First as a baseline, here's a side view of the original U/F:

Next a side view of the Comet U/F:

And finally, the hybrid:

Here's a view of the three undeframes from underneath:

Some comments on the process.

1) Comet underframe.

The floor is etched with the center struts as a fold up, but leave this until later.

The sides fold up and are reinforced by solder. These are designed for brass sided coaches so I found that the sides wouldn't go into the coach body when vertical. I folded that at an angle to provide a lead in. I also removed the floor retention tabs and thinned the coach sides by scraping with a knife. The U/F can be made to fit.

Solebars are tabbed so installation is not an issue, however, before fixing, the stepboard must be considered. There is no location device in the kit for this. The instructions call for drilling 0.7mm holes to accept wire that will support the steps. I marked a line 1mm up from the bottom of the solebar, while it was still on the fret and drilled at each tab.

Install the solebars next. Now, here's what I should have done: drilled for 0.020" and run 0.020" wire through both holes widthwise in the solebars and solder. Next take the step (the 2mm wide strip on the fret) and, starting from the center of the coach, solder it to the support wires. With these running across the width of the coach they won't go all floppy when the solder melts. Do this for both sides. Then reinforce with more solder along the length. I found the 0.032" wires to be too thick and obtrusive. When happy that the step is straight, cut the wires inside the solebar and grind/file flush. I also ground the support wires from under the step - the extra reinforcing solder will hold the step in place.

The center struts can now be folded into position now and soldered.

You will find there is a big hole in the floor of the U/F. First, I took the weight from the original underframe and glued that to the inside floor. When dry, I cut out 0.020" plastic card to shape and glued that to the outside floor to fill the cavity.

Solder the V hangars and voltage regulator support frame.

There are two lots of whitemetal lateral struts. These will need filing and fitting. I used cyano.

To fit the oil valves, drill a 0.020" hole in the inner strut (the location of these and other components can be seen on the instruction sheet that you download from Comet's site). Drill a hole in the valve support and glue wire to it. Fix to the inner strut with cyano. (I always like to pin small components).

I added a representation of brake rodding and dynamo belt.

I used the pinion from the plastic underframe, cut to the appropriate length to support the bogie.

2) Hybrid underframe.

Remove all the detail from the underframe. I used a Dremel with cutting wheel for this. Then, with the Dremel, cut through the floor and remove everything up to the end of the struts. Make the hole done by the first cuts too small, it's very easy to remove too much. Once you have the hole, remove material up to the bevel. Leave enough material for strength.

You will need to cut the Comet floor to the same length and width and the hole you just made. It will take some fettling to get both parts to fit nicely. The Comet floor needs to be about flush the bottom of the plastic floor.

Carry on as before soldering and fitting components.

Make two pieces of plastic card to overlap the hole by the distance from the edge of the Comet floor to the weight. Glue to the inside floor (I used Contact Cement). Next, make a filler piece of 0.040" card to the width of the overlap and glue with styrene cement.

Glue your Comet sub assembly to the bottom of the coach. Finish up the details.

A bit of trivia: the plastic U/F weighs 80 gms, the hybrid 100 gms and the Comet 120 gms. I don't think it matters all that much since most suburban trains we run will have 2 or 3 coaches - occasionally 4.


I think both models look the part. Once painted I think one will be hard pressed to tell the difference. Both are a lot of work, for different reasons. I'm inclined to go with the hybrid because it's a drop in replacement.

8 May 2012

Having decided to use the hybrid method I spent an hour or so this morning, removing the detail from 2 underframes, shown here:

Width of hole is 30mm, length from end of U/F to hole is 54mm.  Length of hole is 117mm.

The next step is to build the Comet module and pack the U/F to receive it.

At the top is the packed U/F (white plastic) upon which the Comet module will sit.  At the bottom is the floor side of the U/F showing packing pieces glued on.  The plastic U/F is about 0.060" thick.  At the bottom is the Comet module with the weight glued to it.  The modules are cut to length but not yet cut to width.  There is not a lot left of the module once the struts have been folded up - the weight provides stiffness to the module.  0.020" card was glued into the cavity to give a flush floor.

9 May 2012

I spent some time today cutting, filing, grinding and otherwise fettling the Comet modules to acheive a snug fit in the underframe.  These have been glued into place:

12 May 2012

I started adding details today:

The V hangers were soldered in and all but the center struts glued in place with cyano.  Battery boxes were fixed with contact cement.

14 May 2012

I completed the underframes this morning.  I did discover that the Bachmann underframe is incorrect for brakes and the battery boxes should be directly opposite one another:

I painted the four underframes with grey primer:

Brakes are at the top.  Now with a coat of flat black:

17 May 2012

I've been putting finishing touches on the coaches.  I spent a day painting figures.  These aren't great but they are good enough to be inside a coach.  Here are a couple of shots of the finished result:

A word about couplings.  I've written about these before but this time I wanted to go step further and try to simulate the vacuum/steam heat hoses.  I reviewed Right Track 4 last night where Tony Wright shows how to install his home made coupling system.  It does work well.  Here are a couple of shots of the couplings before painting:

The brake end of course has a Kadee fitted:

I had to put Comet buffers on this coach because I found that two of the original buffers were broken.

I still have four more coaches to complete but these should be the same as these.

5 June 2012

For the last couple of weeks I have been testing the coaches on the club layout.  I get out there twice a week so it's been a slow process.  The bogie fronts were filed down slightly and the wires from the couplings and hoses were ground down.  I also ground the copper clad strip somewhat so that the bogies could swing and rock freely.  I also had to cut off the buffer heads and reattach them fully retracted in order to stop buffer locking through a double curved crossover.

No comments:

Post a Comment