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Improving The Bachmann 37

Graham Radish


The 2019 release of the DCC sound fitted version i have is a beautiful model it really is, as usual with Bachmann the weight is excellent and so is the body's detail including the wheelset area.


But I need to make people aware of one problem that seems to be affecting a lot of both the modern N scale and OO Bachmann models, its the lettering/logos, they are very fragile, on my 37 i took the shell off to do some wiring upon picking up the body shell with bare fingers i started noticing pieces of the text were missing, i really couldn't believe it! i thought the OO scale variants were more robust in this department as many of my N gauge Farish locos now have most of their factory decals in bad shape, but obviously not, this problem is back again as iv'e mentioned in a forum post i made recently i truly think this is happening because the bodyshell has no protective lacquer layer to stop this from happening.


I have ordered the correct Colas Rail waterslide transfer set to correct the issue, these once done and sealed will be far more robust than the factory print. In the end the bodyshell will be coated in a gloss finish i really do not like the factory satin and of course in real life locos are gloss not satin, the only two parts that are going to be done with a matt finish are the roof and the wheelsets/bogies. I know i know...


At the moment i'm working on the electronics side of things an am leaving the cosmetics until last, every single component on the PCB has been removed as they were causing various small but annoying problems, the suppression components have been replaced with jumpers (staples are a perfect fit) the only two components left on the PCB are the two resistors for the cab lighting, i have replaced the factory 1.5k resistors with two 4.7k Ohm resistors, the cab lights were way too bright and the wrong colour, therefore i also replaced the dark yellow LED's with SMD 0402 warm white at both ends, both the cablights are now wired to AUX1 and AUX2 of the loksound 5 decoder, the tail lights are now wired to AUX3 and AUX4, iv'e taken the CAB light switch at the bottom of the model and have repurposed it to something far more useful to me, it now switches on/off the internal 680uF capacitor circuit, i simply scraped off part of the letter B to a letter P so now it says CAP and not CAB, the tail light switch i have rewired to switch off the tail lights at one end (opposite the driver) doubt i will ever need to use it though as the model will never be run on DC current. Basically now every lighting function is separated. 


As you may know these loksound 5 DCC decoders have a massive amount of functions, so now AUX5 and AUX6 operate dial instruments in the cab, i must say it looks very effective, i used a piece of PC plastic dust mesh to model the 5 main dials of a real class37 found directly in front of the driver in the holes i used tiny pieces of optical fiber cable, these are fitted with 10K Ohm resistors at either end, therefore they are dimly lit just like the real thing but are very noticeable when they're switched on, the factory fitted driver has had a haircut, i have filed down his hat and reshaped his head (poor bloke) he looks much better now. After working on N gauge models for many years i'm finding OO a doddle!


Going back to the dust filter plastic mesh, i cut a square piece of this and attached the roof fan to it, this will now allow the sound to come through the top properly without any obstructions, i have ordered some Square shaped sugarcube sealed cabinet speakers, for this loco and future class 37's i got these from the Roads and Rails shop on ebay. I've heard how good these little speakers are on the Roads and Rails youtube channel, i really couldn't believe the difference compared to the much bigger factory fitted 8ohm oval speaker, the difference is immense the 20x40 factory speaker is all midrange, it has no bass whatsoever and has a sound that grates on me even in an enclosure, these tiny sugarcubes totally destroy them in sound quality and they're half the size!


Here are a couple of pictures, i'll keep this updated as i work on it.






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I've already done all the lighting, now it's on to the sound. As i mentioned the square enclosure type sugar cube speakers sound amazing for their size, Roads and Rails sell these pretty cheap and they are guaranteed to fit all Bachmann 37's without cutting up your model, however there is a simple mod you can do to this speaker to make it sound even better and gives  a few more Hz in the bass response, this is simply done by taking the back off the speaker carefully, then fit the speaker to its designed area with silicone sealant, the surface area of the back of the speaker is now greatly increased, unscrew the PCB for the cab light so you have access to all angles of the speaker, run a bead of silicone around the edges of the speaker box and gently drop it in to place then leave for a good hour before continuing to the next step.




After an hour or so mask off any edges best you can then apply another thin layer of silicone to the joints on the chassis to make sure the speaker is completely air tight, silicone serves 2 purposes, one to stop any air leaks and secondly it provides excellent sound dampening to stop any vibrations that may occur, after this mod is done this little speaker will sound even better as the chassis is acting as a speaker box extension this nearly doubles the surface area of the enclosure without adding any height to the speaker at all.


Note, make sure all your wiring is done properly before you do this, since i have no intentions of ever removing the speaker or the decoder this is not a problem for me.
In this picture you can see that i removed all the PCB components as they serve no purpose on DCC but ive kept all the parts anyway in a little plastic bag and put it in the models box.





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Here you can see that I've also fitted a piece of this PC fan filter mesh to the top of the speaker, these speaker drivers are delicate and this prevents any damage to them, the silicone i used was a tube left over from when i did some work on my bathroom. its "Bond It WP70" it doesn't smell or make a mess like the old silicone sealant, in fact it smells quite pleasant -  it's amazing stuff for metals and plastics and you can get it in about 8 different colours. Of course i could have used black tack but i wanted a more permanent solution.


The sound from the loco now is great, very throaty with good bass and no vibration, im still amazed how much sound these little speakers throw out and with them being so small they're my no.1 choice now for small spaces, they are epic. I wish i could say the same thing about my DCC concepts rolling road though, to be honest it aint great.


With an ultrafine 0.5mm tip marker i've picked out the raised details


The 680uF low esr capacitor is fitted along with the diode and 100Ohm resistor. At the side of the speaker is a piece of plastic i had lying around out of an old airfix kit to tidy things up. A 680uF capacitor is ideal as it provides excellent power continuity with perfect running without having inaccurate running in train controller. And as i mentioned previously the CAB switch now turns the stay-alive off and on.









Edited by Graham Radish
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  • RMweb Gold

Have a look at this that shows some of the back bulkhead of the cab of a 37, very little there is black.

Cab detail of 37254



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  • RMweb Gold
8 minutes ago, Graham Radish said:

Cool, wonder if the colas interior would be this colour at the back?

Almost certainly. 


Sorry to bear bad news but the cab bulkheads you have there are only correct for number 1 cab, the number two cab bulkhead only has a single door into the engine room (on the left as you look at the back of the cab) and a lot of smaller electrical compartment doors as per the photo.



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No andi i'm glad you told me this! My driver is fitted to the side where the fan is, i take it then this side is where the engine door compartment should be?


Thanks for letting me know, a great help. i think i have some satin baby blue acrylic in stock.

Edited by Graham Radish
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Well back on to the lighting, i thought it was all done but there's an annoying issue with the directional marker lights, they're too bright! and were overpowering the main high beam, so i removed both ends of the body and rectified the problem.


Here you will need to replace 2x 0805 SMD resistors at either end, i have marked the image i took to show you which ones to replace, the factory fitted ones were only 1.5K Ohm this results in the marker lights being blindingly bright and this is not prototypical at all, the main white beam supposed to be much brighter, anyway the problem is now solved, once done simply use a good glue for plastics to fit the ends back in place. do NOT use superglue! 








Edited by Graham Radish
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Now the bodywork,


This is the first time I've ever fitted waterslide transfers to a loco so here goes, i'm halfway through doing one side, the Bachmann printed decals came off with my fingernail really easy as expected.


Just done the 'Colas' and 'Rail' decals nearly done one side then on to the other, i've applied them with an 80/20 mix of water and PVA to strengthen the bond to make sure this never happens again.




Once all the decals have been done the main body will be getting a coat of gloss varnish and any areas like windows that need to be masked will be masked with humbrol maskol. when the sides are done the roof will be getting a light coat of varnish thats in between matt and satin in sheen, light coat of sleeper grime on the bogies and some black wash here and there to bring out the details, obviously the black wash will have to be done first.

Edited by Graham Radish
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