Two N Scale Turbo Trains, 50 Years Apart

[peteski]

Looking  good Dwight.  Pretty creative use of the springs.  I'm thinking that if you used springs on the ends of both adjacent cars, you power pickup scheme would be even more reliable (as each bogie would redundantly power both cars).

It appears that you use an experimenters breadboard with standard 0.1" (2.54mm) spacing and connectors with corresponding pin spacing.. A agree that those are rather bulky for N scale.

I have used various connectors with tighter pin spacing, obtained from various sources.  Lately I have settled on making my own from headers and receptacles with 0.050" (1.27mm) spacing.  Those come in single and double row spacing, but they are quite pricey. I just buy multi-pin headers, then using razor saw cut off how many pin connector I need.  The problem is that the pin spacing will not line up with the solder pads on your board. I either etch my own PC boards, or wire the connectors.  For single row connectors here are Digikey part numbers:  ED8250-ND and ED8450-ND.

[Dwight in Toronto]

Peter - thanks for the heads-up on those smaller connectors … they certainly appear to be more synergistic, size-wise, for N scale applications.  I’ll try to source them from the Digikey Canada site.

The idea of duplicating the powered single axle bogie and conductive springs on each coach is feasible.  It would be a lot of work, and although I’m not opposed to it, I think I’d like to run the simpler version for a while, and perhaps revisit this option later on.  I just ordered a bunch of Kato parts, including a few more powered passenger trucks and spare wheels, with the thought that I might want to use them to make all-new, Kato-derived single axle bogies at some point.

I’m happy to report that the single axle track power pickup assembly, located at the rear of the lead cab, singlehandedly enabled the loco and two cars to repeatedly travel around my inner Unitrack test loop, which includes a challenging S curve.  I have since wired up the front driven bogie as well, so overall performance is now far superior to the original design.

At this point, I’ve modified all five units with my “pivot post with springs” coupler design, and have verified that everything is running remarkably well on DC:




Next steps- make up all the vestibule covers, install a LokPilot decoder, and see what I might be able to do for the 4-lamp headlight cluster.  Although a LokSound install would have been nice, the slide-out electronics module doesn’t have room for a speaker.  Not only that, but this 50 year old mechanism is significantly noisier than today’s models, so much so that the gas turbine sounds would have been compromised, so a sound install doesn’t make much sense.

I received a PM suggesting that it might be possible to modify a more recent mechanism, so as to have a more modern, quieter chassis.  Imagine, for example, “chopping off” 1/2 or 1/4 of the length from, say, a Kato or Atlas chassis.  Intriguing, for sure, and something I might just have a go at on some rainy day!

I also need to carry out some cosmetic airbrushing and touchups.  The old Bachmann set is significantly grubbier than the spic-&-span Rapido set, and a lot of that grime would likely wash off with a bit of soap and water.  However, I’ve come to kinda like the older, weather-beaten, hard-earned ’patina’ that graces the old work-horse, so I think I’ll let it be for now!

[peteski]

You are making progress for sure.  Nice job!

[nickelplate759]

Wow!

As for that "4-lamp headlight cluster",  if you look closely at photos I think it's actually three lights and one horn.

Turns out that's not true - read on for the correction.  Fuzzy memory...

[Dwight in Toronto]

Wow!

As for that "4-lamp headlight cluster",  if you look closely at photos I think it's actually three lights and one horn.

Huh, good to know, and certainly sounds feasible.  Makes my challenge a little easier!

With the Rapido model, the oncoming power cab has two lamps on the upper right & left, with a gyro light in the lower left, and no illumination in the lower right position.  When direction is reversed, that lower right is a blinking red end-of-train marker.

[peteski]

[nickelplate759]

Oops, turn's out I'm wrong!   The lower-right (facing forward) light is indeed a light, but it's red, and not normally illuminated.
The horns go in the notches just to either side of the top of the nose doors (in black part of the nose in Peteski's photo).

[Dwight in Toronto]

Ok, so Rapido’s setup is correct, with the blinking red lamp in that final “quadrant” as a rear, end-of-train marker.

I think I’ll forego the red led, simply because that old Bachmann Turbo will very rarely ever be operated in reverse.  I’ve managed to get it running in the forward direction, better than it ever has before, so I should probably be content with that!

[peteski]

Ok, so Rapido’s setup is correct, with the blinking red lamp in that final “quadrant” as a rear, end-of-train marker.

I think I’ll forego the red led, simply because that old Bachmann Turbo will very rarely ever be operated in reverse.  I’ve managed to get it running in the forward direction, better than it ever has before, so I should probably be content with that!

Dwigth, I don't think the red light is used when running in reverse.  Turbo train is a dual-cab setup. It can run "forward" in both directions.  The red light is not a reverse light, but the end-of-train marker which is illuminated at the end whichever is the rear of the train at the time.  At least that's how I understand it. Your Rapido set should show the red light illuminated at the rear of the running set.

[Dwight in Toronto]

Yes, Peter, right you are.  And I did indeed refer to the red lights as end-of-train markers, but I should have been more clear on why I will forego trying to include a red LED as part of the leading locomotive light cluster.  Let me try again.

Unlike the fully bi-directional Rapido design, the Bachmann model was predominantly meant to really only ever be run in the forward direction, with the single motorized cab pulling the coaches and dummy cab.  Although the powered cab will technically operate in reverse, that puts it in pusher mode … a risky, derailment-prone undertaking with those single axle trucks.  So, running it in reverse to replicate the ‘dual-cab setup (whereby) it can run “forward” in both directions’, as you describe, is not practical with this old set.

All I was saying was, if I included a red LED in the powered cab, I would have to run the loco in reverse (ie -pusher mode) in order to illuminate that LED.  For the above reasons, that doesn’t make much sense.  Since the Bachmann lashup will only ever go in the one direction, adding a red, ‘always on’ LED to the dummy cab in the rear would be more plausible. 

Oh, but I do enjoy our discussions!

[peteski]

That makes sense Dwight.

[Dwight in Toronto]

Quick update:

- primed and airbrushed the vestibule covers black, as per the Rapido model:



I thought Lee might appreciate that vintage station and tower set (I also have the water tower somewhere); is there anyone in N scale who never had those pieces!


- started examining how to add LED’s to the lead power cab … first, managed to slice the glued nose cone off of a spare shell (and elevated my appreciation for Kato’s practice of snap-fitting all their components together):




- made up a small insert for the back side of the nose cone, upon which I will try cementing three styrene tubes, with the grand plan of using those tubes as slide-in receptacles for 0402 white LED’s (LED retaining tubes, if you will):




I suppose it’s time to make a start with the LokPilot install as well.

[peteski]

I wanted to say that this Bachmann toy model is not worthy to be equipped with an ESU decoder, but after all your modifications it now seems worthy.

[Dwight in Toronto]

Thank you, Pete, for your endorsement!  At around $45 Cdn, a LokPilot decoder is, in the overall scheme of things, an entirely affordable project component.

I’m continuing to experiment with how to equip the nose cone with a couple of LED’s.

Here’s the iteration that I think I will go with.  In this pic, the ‘retaining tube’ with the 0402 prewired LED inserted would be configured as the gyro lamp, situated in the bottom/left light port.  For the upper right & left lamps, I’m hoping that a single 0402 LED, inserted in the centre retaining tube, will cast enough light through that hollow tube ‘T’ arrangement:




And here’s a closeup showing the tight tolerance where the nose cone and LED retaining tubes need to be re-attached to the shell:




In practice, the two prewired LED’s will get inserted into the styrene tubes, and held in place with small dabs of sticky-tac.  In this way, they are semi-attached to the shell, rather than permanently tethered.  This technique was recommended to me by a RW member, back when I was posting an upgrade thread for an old Bachmann PCC streetcar.  It’s been my go-to method ever since.

[Dwight in Toronto]

Well, I reattached the nose cone to the power cab, installed the LokPilot into the electronics module, and soldered all the related wiring. 

I simply had to know if a single 0402 LED would appear as two distinct side-by-side upper headlights.   And … YES!  The ‘T’-shaped splitter/light tube idea was a success:




I used an 1800 ohm smd resistor for the LED, and it is still overly bright, such that there is more light bleed than I would have liked.  I’ll either live with that, or I’ll try toning down the brightness with software.

I’ve set up the lower left AUX output to generate ESU’s Mars lamp effect, but I need to order additional prewired 0402 LED’s. 

Now to finnagle the wires into the shell, get everything back together, and see if/how it runs on DCC.