Garden Railway Forum

I was asked to convert a couple of Bachmann Big Hauler 4-6-0 locos to battery RC.


When I took the second one apart I was surprised at how different it's mechanism was to the first loco I had just finished converting.

Also, its fittings and the quality of its plastic were poorer quality. It turns out there were at least six "Generations" of the model - each with different mechanisms. They gradually improved the quality over time.
https://www.girr.org/girr/tips/tips1/bi ... _tips.html

Rik

As fate would have it I have just been gifted a Bachmann Big Hauler set which contains the No 10 loco.
How did you do your conversion leave the internal boards or gut it and start afresh?

GAP wrote: ↑Wed May 20, 2026 6:40 am As fate would have it I have just been gifted a Bachmann Big Hauler set which contains the No 10 loco.
How did you do your conversion leave the internal boards or gut it and start afresh?

Hi Graeme
Mostly gutted it. Starting at the front, I replaced the filament bulb with a 3mm LED. I kept the smoke generator in case the customer wanted to use it, I added some lead to the pilot bogie as that seems to derail easily. I stripped out the wiring and removed the wheel contacts then replaced the switch and two pin socket at the back of the cab with a piece of Vero board on which was mounted an eight pin JST socket (a six pin will do - pos and neg for the smoke generator, LED feed, chuff cam output and the two leads to the motor).

In the tender, I removed the chuff board and the mounts for the 9v PP3 battery. I retained the speaker and added a Micron soundcard and an MR603 receiver. I made a 3S battery pack from three 4.5Ah 21700 li-ion cells (with BMS). I reprogrammed the receiver to trigger all the sounds using the buttons and switches on a Micron Tx22X transmitter. I mounted an on-off-on switch and charge sockets on a 3D printed mount so they are accessible when the flap for the PP3 is opened.

Rik

I’ve noticed the variable quality of these too. They’ve been reliable though. I’ve bought a few of these second-hand over the years, to brutally cannibalise just for the chassis. And I recently bought a brand new chassis direct from the US which, I was pleased to see, has a much improved leading bogie arrangement, though you still have to do a bit of work to get it to accommodate more plausibly sized wheels. I have to say your R/C installation is a little more elegant than I’ve managed.

BertieB wrote: ↑Wed May 20, 2026 11:23 am I have to say your R/C installation is a little more elegant than I’ve managed.

Thanks. Mind you, compared with the lash-up which the original loco was wired-up with, anything is an improvement.

Rik

BertieB wrote: ↑Wed May 20, 2026 11:23 am I’ve noticed the variable quality of these too. They’ve been reliable though. I’ve bought a few of these second-hand over the years, to brutally cannibalise just for the chassis. And I recently bought a brand new chassis direct from the US which, I was pleased to see, has a much improved leading bogie arrangement, though you still have to do a bit of work to get it to accommodate more plausibly sized wheels. I have to say your R/C installation is a little more elegant than I’ve managed.

Do they suffer from the dreaded bacnmann gear cracking? I had a 2-4-2 that I had reaired by "barry's big trains" years ago due to a cracked gear. Mine is still new in its box having ever been run. I have a 3 truck shay with a cracked gear that I have to 3 d print a new one for.

GAP wrote: ↑Wed May 20, 2026 10:46 pm

BertieB wrote: ↑Wed May 20, 2026 11:23 am I’ve noticed the variable quality of these too. They’ve been reliable though. I’ve bought a few of these second-hand over the years, to brutally cannibalise just for the chassis. And I recently bought a brand new chassis direct from the US which, I was pleased to see, has a much improved leading bogie arrangement, though you still have to do a bit of work to get it to accommodate more plausibly sized wheels. I have to say your R/C installation is a little more elegant than I’ve managed.

Do they suffer from the dreaded bacnmann gear cracking? I had a 2-4-2 that I had reaired by "barry's big trains" years ago due to a cracked gear. Mine is still new in its box having ever been run. I have a 3 truck shay with a cracked gear that I have to 3 d print a new one for.

According to https://www.girr.org/girr/tips/tips1/bi ... _tips.html some "Generations" are more prone to gear cracking than others. By coincidence, the two Gens (2 & 4) which I've just worked on are less prone to it than the others.

Rik

GAP wrote: ↑Wed May 20, 2026 10:46 pm “Do they suffer from the dreaded bacnmann gear cracking?”

I may just have been lucky but I’ve not had any problems of that sort. Or perhaps I haven’t been running them enough...

BertieB wrote: ↑Thu May 21, 2026 10:21 am I may just have been lucky but I’ve not had any problems of that sort. Or perhaps I haven’t been running them enough...

You've just been lucky.........

Cracked plastic gears aren't just a Bachmann 'feature', other Chinese manufacturers have the same problem.

It's not caused by excessive running, it's design/material related. I have a couple of Chinese made HO diesels that had never turned a wheel, but had cracked gears the first time they were taken out of the box.

Graeme

I think it was the latest Bachmann Catalogue I was reading the other day, and it said that the latest iteration of the Big Hauler 4-6-0 has metal gears now. they certainly had a poor reputation in the gear dept.
Grant.

BTW, I've now blogged the conversion - https://riksrailway.blogspot.com/2026/0 ... r-4-6.html

Rik

I'm considering of using the motor block as the base for an 0-6-0 loco shell I have printed. I was going to use a newquida motor block but this would be better. The tender chassis could be turned into a short wagon.

GAP wrote: ↑Sat May 23, 2026 10:05 pm I'm considering of using the motor block as the base for an 0-6-0 loco shell I have printed. I was going to use a newquida motor block but this would be better. The tender chassis could be turned into a short wagon.

I have 10 Bachmann Big Haulers chassis in service.
One converted to 0-6-0, one to 4-4-0, one to a 2-6-4 tank, two Garratts and 3 basic Big Haulers. I bought the first one in 1994 and it is still the front bogie of my blue Garratt
I have replaced the gears on the blue the Garratt and two of the other locos over the years.
Without Big Haulers I would never have gotten started in G gauge - they were cheap enough for me to afford!
see locos 2, 3, 5, 6, 7, 20, 24, 25. on this webpage for pictures

http://www.trainweb.org/SaTR/locosGall.htm

gregh wrote: ↑Thu May 28, 2026 10:26 am

GAP wrote: ↑Sat May 23, 2026 10:05 pm I'm considering of using the motor block as the base for an 0-6-0 loco shell I have printed. I was going to use a newquida motor block but this would be better. The tender chassis could be turned into a short wagon.

I have 10 Bachmann Big Haulers chassis in service.
One converted to 0-6-0, one to 4-4-0, one to a 2-6-4 tank, two Garratts and 3 basic Big Haulers. I bought the first one in 1994 and it is still the front bogie of my blue Garratt
I have replaced the gears on the blue the Garratt and two of the other locos over the years.
Without Big Haulers I would never have gotten started in G gauge - they were cheap enough for me to afford!
see locos 2, 3, 5, 6, 7, 20, 24, 25. on this webpage for pictures

http://www.trainweb.org/SaTR/locosGall.htm

It was seeing your loco mods and builds which got me started on making my own, Greg. Amazing how many variants you can get from just one type of loco chassis.

Rik

gregh wrote: ↑Thu May 28, 2026 10:26 am

GAP wrote: ↑Sat May 23, 2026 10:05 pm I'm considering of using the motor block as the base for an 0-6-0 loco shell I have printed. I was going to use a newquida motor block but this would be better. The tender chassis could be turned into a short wagon.

I have 10 Bachmann Big Haulers chassis in service.
One converted to 0-6-0, one to 4-4-0, one to a 2-6-4 tank, two Garratts and 3 basic Big Haulers. I bought the first one in 1994 and it is still the front bogie of my blue Garratt
I have replaced the gears on the blue the Garratt and two of the other locos over the years.
Without Big Haulers I would never have gotten started in G gauge - they were cheap enough for me to afford!
see locos 2, 3, 5, 6, 7, 20, 24, 25. on this webpage for pictures

http://www.trainweb.org/SaTR/locosGall.htm

Where did you find the replacement gears? I have a 2-4-2 chassis which was my first loco and I sent it to the US to Barry's Big Trains for a re gear when mine broke. I could 3D print them if I can figure out how to design gears.

I'm now thinking how I can Austrailainise the loco/ tender as the chassis is to long for the printed shell, the 2-4-2 would fit even if I remove one of the trucks either Front or Rear.