So, this train set is pretty cool,  
but there’s a couple of issues. One is it’s 
just unbelievably loud. So, if we turn it on,
you don’t really want that in your living room 
all the time. So either we need to disable the  
sound or have some kind of some kind of 
volume control. The other problem is it’s  
battery powered. So all the batteries are 
in the coal carriage. Now it takes four AA  
batteries. So I just want to check the voltage 
that’s coming out of this. See if these are in  
series or parallel. So let’s see how much volts 
we’re going to need. Got my multimeter here. Um,  
let’s shove this down the end and then 
measure. So, we got 5.1 volts. So,  
these batteries are pretty flat. So, we got four 
AA batteries. So, I think normally this outputs  
um 6 volts. So, we’ll put this to 
one side. Make that rechargeable.
Let’s have a look inside the engine and see how 
it works. So, I can see some screws down here. So,  
let’s try taking those off. I assume you 
undo those screws and this whole green part  
um comes off by itself. I think the speaker 
might be in here. So, let’s give that a quick go.
That’s one part removed. Can see the motor. Uh 
I think this looks like some some kind of weight  
just to uh weigh it down a bit. Um, obviously 
the electronics is still locked away in here. So,  
it’s a screw in here and two screws 
here. So, let’s give that a go. So,  
oops. Wheels will come out and these 
two these two metal bars pop out.
Okay, so that was surprisingly simple once 
you remember to take all the screws out. So,  
as you’d expect, we have a little PCB with 
the usual blob chip on it. So, nothing too  
exciting there. Um, there’s two wires here that 
go off to the speaker. So, if you look down here,  
you can just about see these two yellow 
wires are soldered on to the speaker,  
and then these two red wires go to the switch. 
So, there’s a fair amount of room in there. So,  
I think we could um could do something quite 
clever. Yeah. So, there’s one red wire coming  
from the power going up to the switch that then 
comes back to the PCB. And then this green wire  
just goes directly to the PCB. And then these two 
wires are running the motor. So, let’s dig through  
my bits and pieces and see what we’ve got to mess 
around with this. See if we can improve it. But  
before we get on with some train surgery, let’s do 
a quick shout out to the channel sponsor PCB Way.  
We’ve had a bunch of PCBs from them in the past, 
including my nice little dev board. So, we’ll be  
doing some follow-up projects and we’ll use them 
for that. Check out a link in the description.
Okay, so I’ve looked through all my bits and 
bobs and we got some options. I got these two  
batteries. Um, they’re quite low capacity, 820 
mAh, but we could um double them up in parallel.  
or we have this 18650 cell which um would give us 
plenty of power. Now I think this should fit. Um  
but let’s double check if it will actually fit. 
And then I have this um nice battery charging  
board that has the battery protection IC, the 
charger chip, and it’s got the boost circuit. So  
we can adjust the output voltage using this little 
adjuster here. So we should be able to get 5 volts  
from our 3.7 volt battery. But let’s check if it 
actually fits first because um could be wasting  
our time if it doesn’t fit. Okay, so this is an 
interesting challenge. Um there would be room for  
the battery if we chopped out this red container. 
Well, it did take quite a bit of chopping, but  
um we managed to do it. So now the battery slots 
in nicely. There we have the cable. So, if we just  
pull that up this way out of the way, then we can 
slide this back on. And if we align everything  
perfectly, then we should come back together. So, 
we have the battery terminals coming out here. We  
got the wire going to the plug here. I’ll have 
to pull that back through a bit. like the strain  
relief here and not in the cable. Very good. So, 
yeah, I think we can make this work. I think what  
I’ll do first is I’ll wire the battery up and then 
we’ll adjust this to actually get 5 volts out. So,  
let’s do that first. Okay, so the battery is 
wired up and I’ve adjusted it so we get around  
5.5 volts coming out. So, if we just measure on 
these outputs, 5.52. So, that’s pretty reasonable  
or 5.47. 47. It’s close enough anyway. So, that’s 
a good battery voltage to put out. It’s like a  
kind of four AA batteries that are in between 
fully full fully charged and going flat. Now,  
we just need to solder up the two wires here. So, 
I need to strip some wire and solder it up. Okay.  
So, in theory, this is all wired up. Um, not too 
happy about this capacitor flapping away in the  
breeze. So, I’m going to stick some electrical 
tape around that. Okay. Not the cleanest job,  
but um I think it will do. So, I can stick that 
there. That sits on top there. Let’s get this back  
together and see if it actually works. Let’s just 
do a quick uh sanity check to check polarities  
because sometimes these people put red instead 
of black. So, let’s shove that in the end there.  
Put that there. 5.5 volts. Now, if I remember 
correctly, the center one was positive. Um,  
always forget to try and remember these things. 
Remember, so let’s plug the train in and see what  
happens. Now, I have disconnected the speaker, 
so there won’t be any sound, but wheels go round.  
Perfect. So, that should work nicely. Let’s 
just deal with the super loud speaker next.
Okay, so on to the loud sound issue. I 
think I’ve got a thing that will work.  
What I’ve done is put a potentiometer in line 
with the speaker. Now, if we turn this on,  
let me just uh arrange things so it doesn’t try 
and drive off the desk. So, we’ll turn on. So,  
currently we have very quiet. You can barely 
hear it. All you can hear is the motor.
Now we have maximum volume and we can turn 
it up and down. So I think that will work  
nicely. Let’s just turn this off. So what 
I’m going to try and do is shove this up  
here. I’m going to chop the top of this off. 
And I’m going to stick the top onto here. And  
that will let us turn the knob and adjust the 
volume. So, let’s do a bit of chopping. Um,  
I’ve no idea how well this is going to 
work. This could be a bit of a disaster. So,  
wish me luck. We’re going in and 
we’re going to do some chopping.
Okay, we got there eventually. I need to do a bit 
of clean up work. But uh I think this might work  
quite nicely. So we have our little oops little 
end cap that will stick on there. And where’s it  
gone? And this I can arrange things. Get it 
in the right place. This will stick up here.  
And the end cap will sit on top. Need to just 
arrange things slightly. Bit of clean artwork and  
um bit of hot glue and this will look okay. I 
think I get a bit of sandpaper and just tidy  
this up a little bit. But uh yeah, I think we’ve 
done it. So this is quite challenging. I need to  
stick this end cap on here and then position this 
in the right place so that it’s quite close. Now,  
what I might do, I’ll try sticking this on the 
end first with some hot glue. See how well that  
works. So, let’s use this. So, be quite quick with 
this. So, we’ll fill this up with hot glue. Ouch.
And then quickly try and stick it on.
Making sure it’s reasonably straight.
Okay. I think I think that’s stuck 
on. I don’t know how straight it is.
I think not very, but might be good enough. Okay. 
And now we just need to position this and somehow  
attach it, which I’m not entirely sure how to 
do. So hopefully sufficient hot snot will hold  
this in place. We’ll let that cool down and then 
I’ll see if I’ve got it in remotely the right  
place. Actually looks pretty reasonable. So I’m 
just going to hold it here and let it set. Okay,  
so we’ve got hot snot holding this in place. 
I’ve ended up super gluing this top bit now.  
Hopefully that will actually stick. Um, 
the hot snot wasn’t really holding. So,  
I’m hoping the super glue will do a better 
job, but I’m also hoping I’m not super glued  
everything together because the super glue went 
everywhere um as super glue is often want to do.  
So, we’ll let that set. It’s uh it’s not not 
sticking. Oh, shoot. It’s not sticking very  
well. Um maybe need to leave that for a while. 
Oh dear. Making a complete hash of this. Um
why is that not working?
Okay. So, I think we should leave that 
to set for a while and try not to stick  
my fingers together. So, we’ll leave that 
for an hour or so. Let that set. Okay. So,  
it’s done. The only bit I’m having 
difficulty with is sticking this end  
cap on without gluing myself to everything. 
So, the hot glue didn’t really work. And  
super glue is proving to be very annoying. 
But, it’s not too bad. So, let’s turn it on.  
So, we can turn up to maximum loudness, which 
is pretty loud, or we can turn it down, make  
it slightly quieter. The only slightly annoying 
thing is the drivetrain in this with the plastic  
gears is quite noisy. So, any hints on making 
that a bit more quiet would much appreciated.
Not bad. So, I definitely need to learn 
more patience when it comes to superglue.  
Very quick for sticking fingers together. Not 
so fast on plastic and metal. But now, this is  
uh pretty firmly attached. It’s not going 
to fall off at any time. I put a bit of  
gold paint over the scratch marks. It’s come 
out quite nicely. It is slightly wonky. It’s  
not quite perfectly positioned, but 
then again, it is an artisan repair,  
so not bad. Works quite well. Um, I might 
3D print a replacement at some point,  
but for now, this is pretty good. It will go 
back in the box, ready for next Christmas.