7740 inspired MOC - 6w - Updated locomotive

[LL1982]

Hi,

After lurking and responding a bit I'll give you my creation. I am a fan of the 7740, though I never owned one, i love its colours and just the basic simple playability of it as it represents your typical intercity train. I am a 80s kid so what can I say. We have a PU R40 based track so I have this one build 6 wide. I collected the doors and windows through the last year in several buys and that inspired this build. The locomotive is still based on the old design, but I have plans to make it more like a BR103, but still doubting about 6 or 4 axles. Have not figured out how to use the middle hole on the train motor for a blind yet. I was thinking on adding a 2x2 round with hole there, but I think I may need to use some external structure for it. Adding a pivoting third wheel behind the train motor will result in a very long locomotive which will look odd with the carriages in my opinion. 

I did make the carriages longer than the original. They are 32 studs base and then 2 studs extensions on either side for the connections. I kept the similar arrangement of passenger and diner carriage but rearranged a bit and used different techniques for the roof and ends. Inside the passenger car I also gave first class a different type of seating. I am experimenting with a stripe on the diner car but I may remove that. As the holiday season is coming I also installed some light so that the munchkin and I can have fun running the train in the dark. 

 

 

 

Edited December 4 by LL1982
Image links, updated title.

[idlemarvel]

Very nice. The 7740 is an iconic set.

Ref 2 or 3 axles for the loco,.it's quite hard to use the middle hole in the PUp train motor as it is only 1/2 stud deep. If it was 1 stud deep you could use a Technic frictionless pin with cross axle but it isn't. It would probably be easier to build a custom 3 axle bogie and power it from a motor inside the loco.

[LL1982]

Thanks! Yeah I figured as much @idlemarvel. Means I need to buy a motor, I have train motor spare on a city set that is not running anyways. I had a look on those lego L motors and a few off brand options (thats ok to mention here right?), those red type PF style motors those come with rechargable battery blocks. A custom 3 axle with 1 stud between wheel sets would make it feasible on a 30 stud locomotive for instance. The lego L motor does not respond to a remote right? You need the app? Or did I misunderstand that? Rather not give my kid a phone, point of lego is to play with the bricks and the remote.

Edited November 13 by LL1982

[idlemarvel]

8 hours ago, LL1982 said:

Thanks! Yeah I figured as much @idlemarvel. Means I need to buy a motor, I have train motor spare on a city set that is not running anyways. I had a look on those lego L motors and a few off brand options (thats ok to mention here right?), those red type PF style motors those come with rechargable battery blocks. A custom 3 axle with 1 stud between wheel sets would make it feasible on a 30 stud locomotive for instance. The lego L motor does not respond to a remote right? You need the app? Or did I misunderstand that? Rather not give my kid a phone, point of lego is to play with the bricks and the remote.

You are correct, the L motor does not respond to the remote, or rather it does but only on/off and you have to hold the button down on the remote.

You can use the train motor on its side inside the loco body. Its only 3 studs wide (plus some allowance for the pin on top of the motor) and less than 4 bricks high (lower than the hub) so its doable in a diesel or  electric loco. Then you can use the remote as normal. 

If you need more help a have a few pictures I can upload later today.

[Selander]

In the format you build, (~length and width) I'd advice you to stay with 1-2 standard 2-axle PuP train motors. That will look better with that "toy-ish" original  Lego building style, and the playability is so much better.

A "real" 3-axle technic Lego based bogie with a separate PuP large motor in the loco cabin will need much more length/space/volume than you currently have. Your coaches would also need a rebuild to look appropriate as a consequence. Also bare in mind a 3-axle bogie demands more tweeking and maintenance. 

[LL1982]

Thank you both for your input this is helping me out. 

@idlemarvel i am completely interested in seeing the train motor on its side. I've never considered that. So yeah if you could share please do. 

@Selander I do feel you are right. I will start with this. I bought instructions for a 7wide loc with M motor and I see the issues with getting the drive train proper. I'll enjoy the build for a 6wide locomotive first and get it running and then I can tackle more challenges later on. Let me get a good body first. Indeed I do not want a too big locomotive or else the proportion will be off.  

[idlemarvel]

1 hour ago, LL1982 said:

Thank you both for your input this is helping me out. 

@idlemarvel i am completely interested in seeing the train motor on its side. I've never considered that. So yeah if you could share please do...

Here are some pictures to give you some clues. This shows a 2 axle bogie but the idea is easily extended to a 3-axle. Picture 1 is below and picture 2 above. Picture 3 shows the motor inside a loco, the recent Spiderman Subway car. Use a 7L axle through the motor into the bogie, with a 1/2L bush to hold it in place (yellow in the picture). Hope this helps.

 

 

 

 

 

[JopieK]

Wow @LL1982 thanks for sharing. I might do that to my 7750 some day! Have had it since I was a child. Lighting of the cars also worked out very well.

[LL1982]

Thanks @idlemarvel I get the idea. 

Thanks @JopieK, also for the featured. The 7750 or a steamer in general is on my future wishlist. But before I try getting all those wheels correct I decided to build some Electric or diesel locomotives first. But the 7750 is pretty cool, give it a go. 

Edited November 14 by LL1982

[Shiva]

Nice train set :)

[Gunners TekZone]

On 11/13/2025 at 7:16 AM, idlemarvel said:

Very nice. The 7740 is an iconic set.

Ref 2 or 3 axles for the loco,.it's quite hard to use the middle hole in the PUp train motor as it is only 1/2 stud deep. If it was 1 stud deep you could use a Technic frictionless pin with cross axle but it isn't. It would probably be easier to build a custom 3 axle bogie and power it from a motor inside the loco.

@LL1982

If you are not adverse to a little minor LEGO surgery ... this works...

Trim the end off this Technic piece, leaving the flange.

 

You will need to trim some more on the motor "base" (A Dremel would have been neater, but it is all hidden)

 

Use a "3rd hand" to hold in place when reattaching the base.

 

Fit the wheel, trim the axle and voila... a 3rd wheel on a PU (or PF) motor that has enough wiggle to handle the R40 just fine (although removing the rubber traction band will help even more)

Edited November 15 by Gunners TekZone

[LL1982]

Thanks @Shiva

Wow @Gunners TekZone not sure if I dare trimming the motor base, but the idea is good indeed. I cut down baseplates to suit my table so maybe this could go. 

[Gunners TekZone]

34 minutes ago, LL1982 said:

Wow @Gunners TekZone not sure if I dare trimming the motor base, but the idea is good indeed. I cut down baseplates to suit my table so maybe this could go. 

It almost fits without the additional base trimming, but then the base doesn't sit flush with the top (in the middle) nor will the pin rotate smoothly.  You might get away with just trimming the flange end of the pin to much tighter tolerances.  Experiment there first if you are unsure.

Regardless, trimming out the blocking plate on the base is non-structural, so just go slow and use a Dremel if available (I used electronic flush trimmers and a X-ACTO knife... with a bit of rushed enthusiasm  )

[JopieK]

@Gunners TekZone alas (at least at my front) we/I cannot see your pictures (or is it just that my LEGO purism filter is working as it should haha ;))

[LEGO Train 12 Volts]

Iconic remake of set 7740!

I like the interior and especially the lights illuminating the carriages.

If I may make a point, I would have made the carriages slightly longer and the roof not stepped (this is obviously my opinion).

[LL1982]

@JopieK I can see them and it's still lego, just trimmed 🤣.

@LEGO Train 12 Volts Thanks. Yeah longer is also still on my mind, going towards to 40 studs for instance by adding a window. Allowing for more interior. But I'm a bit wary about my curves and fitting in the sightings. Yeah 4 steps each side is maybe a but much haha but when you're on a roll 🤣. Will take it along for a future revision.

[Feuer Zug]

Great homage to 7740. I love the lighting addition.

[LL1982]

Thanks @Feuer Zug

[-DoNe-]

What a wonderful build you've managed. Keeping the red/yellow color scheme is the right way to go. Had I done it myself I just know I would have strayed away to dark red and tan, which would have made for a less playful build. Extra points for the lit up passenger carriages as well!   

[LL1982]

Thanks @-DoNe- indeed the dark red / tan scheme is great, it has been plaguing my dreams for weeks. I also saw many alternative brick suppliers using that colour scheme and yes it is true to Rheingold. But I decided to stay true to the original Lego scheme.

- Updated locomotive - It has taken me weeks to collect just a couple of parts haha, love some BL stores shipping schedule. But I managed to build up a BR103 version in Lego 7740 livery, with some adjustments. I kept it on 4 axles, sorry for all purists. But making the locomotive longer would pull it all out of scale and I have not yet found an affordable L motor. My build is largely inspired by an image on Holger Matthes his website, he was again inspired by Fouke Boss I understood. Beside that I used some online images of the BR103 and make some interpretations of my own. 

I put a simple switch in parts of the pantograph roof section to trigger the hub. Makes it easier for my daughter to start the train. Its is a squeeze due to the recessed doors, but I managed to get a driver in, I kinda like that little detail. The front lights are powered. Still need to make a movie of it, but you can see some stuff on my IG already.

 

 

 

 

[idlemarvel]

A fitting tribute! Well done. I like the red pantograph details, and the way you have aligned the steps on the bogies under the passenger car, and the curved underpanels.

[zephyr1934]

¸Nice work on the locomotive!

[LL1982]

On 12/4/2025 at 3:13 PM, idlemarvel said:

A fitting tribute! Well done. I like the red pantograph details, and the way you have aligned the steps on the bogies under the passenger car, and the curved underpanels.

Thanks. I stumbled upon the red parts on a lego expo. So bit lucky there. Yeah I'm happy with those coach boogies too. I wondered if such an extension would work on the bends but it works out great.

 

Thanks @zephyr1934

[-DoNe-]

On 12/4/2025 at 2:21 PM, LL1982 said:

Thanks @-DoNe- indeed the dark red / tan scheme is great, it has been plaguing my dreams for weeks. I also saw many alternative brick suppliers using that colour scheme and yes it is true to Rheingold. But I decided to stay true to the original Lego scheme.

- Updated locomotive - It has taken me weeks to collect just a couple of parts haha, love some BL stores shipping schedule. But I managed to build up a BR103 version in Lego 7740 livery, with some adjustments. I kept it on 4 axles, sorry for all purists. But making the locomotive longer would pull it all out of scale and I have not yet found an affordable L motor. My build is largely inspired by an image on Holger Matthes his website, he was again inspired by Fouke Boss I understood. Beside that I used some online images of the BR103 and make some interpretations of my own. 

I put a simple switch in parts of the pantograph roof section to trigger the hub. Makes it easier for my daughter to start the train. Its is a squeeze due to the recessed doors, but I managed to get a driver in, I kinda like that little detail. The front lights are powered. Still need to make a movie of it, but you can see some stuff on my IG already.

 

 

 

 

The updated locomotive looks absolutely stunning. 

[LL1982]

Thanks appreciated. I'm happy how this one ended up.