MOD: 7938 retrofitted into a “Best-of-Both-Worlds” Train

[Toastie]

Dear All,

I have slightly modified the 7938 Passenger Train (see recent review here) into a “Best-of-Both-Worlds” 9V/PF train, featuring passenger compartment lighting, front/rear lights, and “auto-battery-recharge” function, holy moly

The passenger compartment lighting is realized with both 9V (passenger car) and PF (control car) light elements, front/rear lights are PF.

See my BrickShelf gallery for more photographs or the short clip below.

Just briefly:

The loco is equipped with the LEGO LiPo, which is automatically charged on stretches of powered track using a modified 9V motor. 9V … 18V / 1A DC track power will work well, as demonstrated here.

On my track layout I am using a cheap solid state 12V/6A DC power supply originally sold for powering small 12V “car” appliances such as miniature-fridges.

The LiPo is delivering power to the PF receiver and to all lights (front/rear/both passenger cabins) via the LiPo source/PWM output – I needed to save PF channels, since some of my switch points are PF remote controlled. So all lights are permanently lit when the train is turned on and running – guess this is also the case in reality, right? If free channels are no issue then the lights can be switched on/off using the second PF receiver output.

This train runs on 12V, 9V, RC, and 4.5V track. On 12V (with appropriate power pickup element #1151-1) and 9V stretches the LiPo is recharged automatically and delivers power to the train at the same time. On RC and 4.5V tracks the train runs on the LiPo battery. 9V reversing loops are no problem when they are electrically isolated, for example with one RC track element.

Most of the work was going into the car lighting design, particularly for “hiding” the cables in the passenger compartments, so that they hardly show. Also, I wanted the set-up to be modular to eventually add more “electrified” cars (comparable to this). The current design "funnels" the power through all cars finally into the control car. The 9V cables are much more flexible as compared to the PF cables and they make life much easier when it comes to running electricity through the entire train. This was recently discussed earlier in this thread.

Power is delivered from the loco’s LiPo via PF to 9V conversion (PF rear lights) then entirely as 9V in the car(s) (9V cabin lights using 2 x #6035), and via 9V -> PF conversion in the control car (PF front and PF cabin lights). The electric light bricks #4767 or #4771 would have made construction even easier, but I simply don’t have any of those …

Well, the train becomes rather expensive, but it is fun to drive it through the night … even the Brickster is aboard – in cuffs though and guarded, but that does not mean anything, does it!

Regards,

Thorsten

EDIT: Oversized images (2362x1016) removed by moderator. Please review image posting guidelines before posting images this large. -TheBrickster Sorry, I am getting too old, I guess ...

Edited October 2, 2010 by Toastie

[bricked one]

WOW, thats really cool!!!

So is the 9v motor pushing, or just generating power for the interior lights?

[BoobyToy]

Awesome.....I'm gonna have to do something Similiar.

BoobyToy

My Flickr Account

[Mrlegoninja]

Thats really cool!

[Toastie]

WOW, thats really cool!!!

So is the 9v motor pushing, or just generating power for the interior lights?

The 9V train motor is picking up track power through the wheel set, delivers that via a custom cable to the LiPo for "automatic" charging. The LiPo powers the entire train (PF receiver, lights), the PF receiver powers the modified 9V motor via custom cable two.

Regards,

Thorsten

[jamzee]

This is fantastic, have been to Lego Show at Steam today and saw 7938 (I ordered mine on Friday) - this is truly a super train. Have also ordered lights for the front and rear train sections but I really like illumination in the centre carriage too!!!! - I will have to use a spare set of lights in there to get this kind of effect, great video too btw...

I think it is projects like this that are boosting this already good-looking train's appeal massively and we might have a bit of a sleeper hit with 7938, it is hard to explain but I think the design of it looks really "pure"...

Edited October 3, 2010 by jamzee

[legotrainfan]

Wow, that's what I call a real model train feeling! Installing lights to illuminate the train's interior must have been a challenge, but it has payed off! It looks amazing! Quite ingenious way of doing it!

[CarrollFilms]

This is very cool, I need to add lights to my trains, watched the video, but why the hannah montanna music. You did a great job building and seting this all up,keep up the good work

[Toastie]

Thank you all very much for the flowers!

This is very cool, I need to add lights to my trains, watched the video, but why the hannah montanna music. You did a great job building and seting this all up,keep up the good work

Hannah Montana - hmm, we have about 10 DVD's in the house + it was the video camera of one of my daughters, so that uhum was part of the deal .

But more importantly, Hannah apparently favors building across multiple themes (9V and PF) as much as I do, right? Well, I did not know before that she was into LEGO building!

Best wishes,

Thorsten

[Teddy]

That is a very elegant and simple method to use the old 9V motor both as a power pick up for a PF system and as a train engine simultaneously.

[Gareth]

Fantastic.

I thought that TLC would of made a set so that you just install the lights in to the 9v trains like they used to for the 12volt.

It's a good idea very impressive and effective too, I always liked the look of lego trains at night all you need to do is have track side lights and the same in the station too, to recreate those old 80's catalogue pictures.

Great work.

Gareth

[fred67]

Fantastic implementation. I've been arguing for some time that 9V could be modified to get the best of both worlds without requiring the complexity and expense of DCC, I've just never had the occasion to try it out.

So, a big THANK YOU and congratulations on an excellent job... it's WAY more than I would do, frankly, many steps ahead of what I had in mind.

[AussieJimbo]

Great work, Toastie.

The auto-charging from powered track is a brilliant idea.

:classic:

[LEGO Guy Bri]

Great idea Toastie love the interior lights. Are PF lights compatible to hook up to an original 9V motor, like the old lights did?

[benny]

Wah! A very smart train! You upgrade this train into super level!