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Topics: 44   Replies: 60
posted on Mar 22, 2018:

While unpacking some of my stuff, I came across this crane that I had built way back in the 70's when I was was first trying to learn how to build with metal instead of plastic and soldering them together instead of gluing.

This is made out of tin ( using the metal from an old paint thinner can ) and small diameter brass rod.
I have learned a lot about soldering and working thin metal over the years and this model is a little crude compared to the standard that I set for myself now.

This is the crane.
I've taken the back cover off of it so I could put paint remover on it and get it down inside everything.

The first thing to do, was to separate the main parts of the crane.

You can see that the crane boom was mounted using two large terminals for electrical wiring.
The pulleys are made up from putting brass eyelets together on a rod.
I'm only going to modify this enough to make it look a little more realistic but still has some of the oddball things that I used when I first built it.

The base for the crane is a single sheet of tin that extends out the front ( where the boom is attached ) and hangs out past both side of the main body.
I trimmed both sides so they are flush with the main body of the crane.

The gear and pulleys at the top front edge are for the cables that raise and lower the boom.
Originally, I had the cable for the hook running up over the center of these pulleys and going under the center of the lift pulleys out on the boom and from there, on out to the end of the boom.

Now, I made up a bracket with two rollers and mounted it down closer to the base of the crane body.
I want to use a clam-shell bucket on this crane so the cables for it will come out between these two rollers.

A piece of brass is bent up on the ends to form the new mounting bracket for the boom.
I have also soldered 1/4 inch square brass tube to the underside of the base to make it thicker.

I machined a cover out of a piece of brass for the gear on top of the crane.
The cover makes it look a little more realistic and it also has a screw in the back of it that will keep the gear from rotating.

The gear is used to wind the two boom lifting cables up on the pulleys then tightening the screw will keep the cables from unwinding.

If you'll look back at the first photos, you'll see that the framework for the cab is made out of round brass rod.
I want to be able to put glass in this cab so I cut the brass rod out so it can be replaced with pieces of angle.

This side of the cab has a hole in it that was for clearance for the boom mounting bracket.

Here I'm forming the frame for the rear window behind the seat.

The top was also held in place by the brass rod so I decided to just get rid of it and make a new frame for the top from the brass angle.
The rear window frame is soldered in place.

The brass angle is used to form the windshield frame and the support for the top of the cab.

A new roof piece is soldered to the top of the cab.
Remember that hole in the lower part of the cab to clear the mounting bracket for the boom ?
I covered that with a piece of brass.

The I used some narrow strips of steel to frame out a door and soldered a strip of brass along the back side of the door.
This looks kind of gaudy but I think it will look okay once it is painted.
I also made up a door handle and put it on.

Here is how it looks so far with the cab mounted to the main body.

The front and rear window and the two angled side windows will have clear plastic in them for the glass.

I took three straight pins with the little round heads and soldered them to a piece of brass.
This is the panel with the control levers for inside the cab ( I know a real crane has more than three levers, but this cab only has room for three. )

This is mounted to the dash inside the cab.

Next is to build a clam-shell bucket.
Starting with a piece of sink drain pipe, this will form the bottom 'curved' part of the bucket.
I squared the two sides on the lathe and I took a skim cut to remove the chrome plating.

Then I cut two sections from the drain pipe for the bottom panels of the two bucket halves.
The sides are cut from sheet brass and a brass washer is soldered to the hinge point on each piece.

Soldering the sides to the bottom panels.

Trial fitting the two halves of the bucket together and making sure they upen and close properly.

Here I'm fastening 'teeth' to the bottom edge of each half.
Each tooth is soldered onto the cutting edge of the bucket so it over laps the the other side just a little.
They are only soldered lightly so the solder doesn't flow across the surface of the whole tooth and stick it to the edge of the other bucket half.

Then two small holes are drilled thru the tooth and the bucket and two small brass pins are pushed thru them.
The long ends of the pins are cut off about 1/16 inch above the surface of the tooth.
This is place on the corner of the vice and the cut ends of the pins are hammered flat to form a tight rivet to hold the tooth in place.

The teeth are all attached, 3-teeth on one halve and 4-teeth on the other half.

I cut a brass rod to length and drilled and tapped the ends to form the pivot bar for the two bucket halves.
The pulley goes in the center of this bar and is free to spin on the bar itself.
I made up a triangular shaped housing with brass tubes soldered on each side of it.
This is the guard to keep the cable from coming off the pulley and it also keeps the pulley in the center of the bucket.

If you look close, you can see that each of the washers also have two rivets thru them to hold them in place because they are only soldered on 1/4 of each washer.

Here is how it looks so far with everything assembled.

All that was left was to make a top bar and attach the four arms to it and the corners of the bucket.
The arms are valve linkage parts from the Rivarossi 0-8-0 locomotive kit.

The operating cable to open and close the two bucket halves goes down the the small hole in the center of the top bar, then under the pulley and will be attached onto the underside of the top bar.
With the bucket hung from the hook in the center of the top bar, releasing the operating cable will let the center pivot bar drop and the two halves of the bucket will open up so it is only held by the cable attached to the top bar.

The open bucket is then lowered down so it sits on top of the dirt.
Then the operating cable is pulled back up and this lifts the pully on the center pivot rod up and causes the two halves of the bucket to close.

The teeth on the cutting edge of the bucket dig down into the ground as the two halves close so it digs a hole and fills the bucket with dirt.
The whole bucket is then lifted by the operating cable.
The cable attached to the top bar is also raised at the same time but is kept slack to keep the bucket closed.

To drop the dirt, either the cable to the top bar can be raised up to let the operating cable go slack and open the bucket .. or the cable to the top bar can be held still and the operating cable is then lowered to open the bucket.

A drag line from the crane will be attached to the chain that is hooked to one end of the bucket, to keep it from spinning on the cable and also to help position the bucket.

MOW crane
Topics: 69   Replies: 117
posted on Mar 21, 2018:

Fresh from a five year overhaul in 1897 per B&O practice, Staten Island Rapid Transit Forney number 18 with white flags returns to St. George for it s first scheduled assignment, after a 5.5 mile shake-down run to Arlington.
Forneys like this were used in commuter service on some late 19th century roads and were bi-directional and did not need to be turned at the end of a run.
This loco is equipped with the Eames vacuum brake, as seen by the vapor ejector on the cab roof.
Vacuum brakes were ideal for short trains making frequent stops often less than a mile apart.

Test Run Extra
Topics: 16   Replies: 16
posted on Mar 10, 2018:

A positive DC offset of several Volts triggers the horn/whistle on O-gauge conventional control. Any engine with a horn/whistle has this detector circuit built-in. And there are after-market boards or upgrade modules with same detector capability. You can roll-your-own DC offset detector for less than $1 in parts. And if the application of DC offset detection is to simply flash alternating LED ditch lamps, you can integrate both functions for another $1 or so. There is a lot of tedious component-level assembly.

Two wires on the left bring in AC track voltage. When DC offset is detected, the two white LEDs (3mm diameter suitably sized for most diesel engine ditch lights) alternately flash.

In action:

The trick, if you can call it that, is to isolate or separate the DC offset from the 60 Hz AC voltage. You are trying to find a few volts of DC in the presence of 18V or more of AC. The filtering of the 60 Hz is a simple Resistor-Capacitor filter shown above using a 100K resistor (R5) and a 4.7uF capacitor (C4). This is a simple 1-pole filter with a time-constant of RxC = 100k x 4.7uF = 0.47 seconds. This is equivalent to a so-called corner frequency of 0.3 Hz. Such a filter will knock down the 60 Hz AC track voltage amplitude by some 100 times. So the 18V AC gyration are become less than a 1/4 Volt which in effect leaves just the DC component of the track voltage. This filtered detector voltage triggers a pair of transistors set up in a so-called Darlington configuration which essentially turns on when its input exceeds about 1.2V DC. When the Darlington-pair turns on, it provides 5V DC power to a widely used oscillator circuit which flashes a pair of LEDs.

The circuit uses readily available, low-cost components available in thru-hole or surface-mount packages depending on your preferred assembly method. C4 should be non-polarized uch as a ceramic or bipolar type.

If the 2 input wires are reversed to the track, this circuit would flash the LEDs when the Bell button is pressed - that is, when a negative DC offset of several Volts is impressed on the AC track voltage.
Alternating ditch light flasher for conve...
Topics: 44   Replies: 60
posted on Mar 4, 2018:

Thought I would like to build a model of a Garratt locomotive next so I went searching for some photos of them on the internet.

Being mostly ignorant of equipment used on railroads in foreign countries, I had thought that this type of locomotive was only used in Great Britain and that they only made one style of this locomotive.
Boy .. was I in for a surprise .....

I quickly realized that the Beyer-Garratt steam locomotive was used all over Europe and some of them are still in regular use in Australia and Africa.
They were built as small as a wheel arrangement of 0-4-0 + 0-4-0 all the way up to 4-8-2 + 2-8-4.
Here are a few photos starting with the smaller locomotives and going to the bigger ones.

They also show up in a variety of colors.

Some photos of a couple of the locomotive that are still in operation.

SO .... after spending some time looking at photos of them and seeing some of them running on Youtube, I started digging up parts to start building my model and this is what I have to start with.

These are parts of two European 0-6-0 locomotives that are plastic models made by Pola Maxi in Germany.
They are suppose to look like this but my two models have seen better days.

I'm going to build a 0-6-0 + 0-6-0 so I stripped the two models down to the basic chassis by removing the side rods and valve linkage and the steam cylinders.
The steam cylinders are the wrong design and the side rods and valve linkage are all plastic so I'm not going to use these parts.

The Garratt locomotive has a front and rear set of drive wheels with the water tank sitting over the front set of wheels and the coal tender is over the rear set of wheels.
The boiler is mounted on a carriage frame work that is hung between the two sets of drive wheels.
Each set of drive wheels has the steam cylinders at the far end of the chassis and it pivots at the other end where the boiler is mounted over the end set of wheels.

The first problem that I see is the electric motors on the plastic models is in the cab with the steam cylinders at the front.

I can't make the pivot mount for the boiler carriage on the opposite end from the cylinders because the electric motors are there.
So I need to mount the steam cylinders on the end with the electric motor so it will be hidden inside the water tank and the coal tender and the carriage for the boiler can then pivot on the other end of the two chassis units.
( Whew ... I hope that wasn't too confusing ? )

Back to my old standby of parts for building plastic locomotives, I'm milling the top off a steam cylinder from the Rivarossi 0-8-0 locomotive kit.

The tops are milled off both steam cylinders and I'm gluing a piece of styrene on top of them.
The individual parts are shown in the foreground and the piece of styrene is clamped onto the cylinder in the back ground, waiting for the glue to dry.

The next problem is the plastic models have the center drive wheels connected to the steam cylinders and the Garratt locomotives have the far end drive wheels connected to the steam cylinders so I need to switch the wheels.

The crank pin and eccentric lever are made from plastic on the model so I have to make new crank pins out of steel rod for the rear drive wheels.

The steel crank pins are made up and pressed into the drive wheels.

The center wheels and the end wheels have been switched and the crank pins are pressed into the end drive wheels.
The other two pairs of wheels have the crank pin hole threaded so I can screw a small shoulder screw into them to hold the side rods in place.

So far .. I have a pair of 0-6-0 chassis units, steam cylinders that will fit them now, brass valve linkage ( That I think I can make work ) and the main rods for the steam cylinders.
I wasn't able to find any side rods in my parts that will fit the wheel spread on these two chassis.

So I'm going to machine the side rods out of some strips of brass.

The side rods are finished and mounted on the two chassis.

The steam cylinder is mounted on the end of the chassis with two small screws and the electric motor is set in place.
The main rod is set into the guides on the cylinders and on the crank pin to see how everything fits.

The top of the chassis frame on these drive unites sits about 1/4 inch higher than the top of the frames for the 0-8-0 locomotive kit.
I had to mill out the underside of the steam cylinders where they sit on the top of the frame so that the cylinders sit down low enough to line up with the wheels.

So the support for the cross head guide rails has to be milled out so that it sits lower on the frame also.
The support on the left is the stock unit and the modified support is on the right.
The two little white blocks on each side is where the holes were drilled for fastening this to the front of the valve linkage frame with two small screws.

The front part of the brass valve linkage assembly has to be shortened in order for the front linkage arms to reach up to the steam cylinders and the rear linkage arms to fit back to the rear wheel.

The stock brass valve linkage assembly is on the left with the stock cross head guide support in front of it.
The shortened valve linkage assembly is on the right with the modified cross head guide support attached to the front of it.

Seeing as how the steam cylinder and guide support had to be lowered for them to fit .. you would think that I would have realized right away that the valve linkage is probably going to have to be lowered also ....
Well I didn't think about that until I had everything assembled on the chassis and got right down at eye level to take this photo.

It was then that I saw that the pivot point at the end of the front linkage arms is still sitting higher then the slide bracket on the upper part of the steam cylinders.
This pivot point on the front linkage arms is suppose to rest in the pocket of the slide bracket on the cylinders.

Oh well ... I'll chalk this one up to brain fade and go on from here . ......
I took the brass valve linkage assembly all apart so I could reassemble it with the side frames upside down.

With everything put back together, the pivot point of the front linkage arms now fits snugly into the pocket of the slide bracket on the steam cylinders like it is suppose to.

The valve linkage assembly with the cross head guide support mounted to the front of it is attached to the top of the chassis with two screws.

A matching pair of drive chassis's.

I have left the electric motor off the chassis unit so I can rotate the wheels by hand to make sure that everything works correctly and they won't be put back on until after everything is painted and the locomotive is assembled for the last time.

I'm going to use this frame and floor piece from the tender of the Rivarossi 0-8-0 locomotive kit to build the carriage frame that is mounted in between the two drive units and carries the boiler.

The two parts are clamped together while the glue dries.

Then I milled off the parts for the brake system.

A piece of styrene is mounted on the end of each of the drive units and a counter-bored hole is machined into them for the pivot point with a brass ring set into each of pivot holes.
A round boss is glued onto each end of the underside of the carriage frame that will fit into the counter-bored pivot holes.

Styrene is glued onto the top of the carriage to bring it out to the correct width.
The carriage frame is set on the drive units.

Beyer - Garratt locomotive
Topics: 16   Replies: 16
posted on Feb 25, 2018:

As of February 2018, the MTH website continues to show the use of an NTE50 latching DPDT relay to control a Tortoise switch machine from an AIU SW(itch) port.


The suggested relay is now obsolete and even when in production was quite spendy (over $25). The required functionality to operate a Tortoise switch machine via the AIU's SW(itch) port is a so-called LATCHING DPDT (double-pole-double-throw) relay. Suitable "bare" or loose unmounted relays can be had for just a few dollars but require soldering and such. There are assembled DPDT relay modules with screw-terminals but are around $15 each.

Here's a DIY method for about $5 out-of-pocket and does not require soldering to tiny relay pins. Additional ports would be less the $3 out-of-pocket as a single 12V DC power adapter can power multiple (at least 10) ports.

Again, this method does require careful attention to detail and is perhaps more of a thought-provoking idea than a practical solution. In any case, here's the concept in action ... albeit driving a bi-directional DC motor rather than a Tortoise switch machine.

Note: using this method, when the relay module is first powered, it always starts in the "OFF" or unlatched position. This can be wired to be the "straight" or "diverge" position. The point being this is different than a true mechanically-latching relay which remembers its position between operating cycles. There are features within MTH DCS command-control to set multiple SW ports to a pre-determined configuration.

Note: DPDT relay is used to reverse (invert) the polarity of a DC voltage to the switch machine DC motor. If AC voltage is available to drive the switch machine(s) then only a single-pole SPDT relay is required. This method is described in the Tortoise literature. A latching relay is nevertheless required. In this case, Relay #3 can be the SPDT relay and Relay #4 is not used.
Tortoise switch machine control using MTH...
Topics: 16   Replies: 16
posted on Feb 25, 2018:

MTH DCS Accessory-Interface-Unit (AIU) provides 10 each SW(itch) ports and ACC(essory) ports. You cannot reconfigure an SW port to be an ACC port or vice versa. So if you use up all 10 ACC ports and need one more, it doesn't matter that you have any spare SW ports - buy another AIU for >$100 (MSRP).

Here's a way to get ACC port functionality from an SW port for about $5 out-of-pocket. Additional ACC ports after the first are less than $3. The user-interface will be arguably unconventional in that you will press the SW port "diverge" button to turn ON the accessory, and the SW port "straight" button to turn OFF the accessory.

The star of the show is the 4-channel, non-latching 12V DC relay module for less than $3. Only 3 of the relays are used to make a latching relay that is "set" when the diverge button is pressed, and reset when the straight button is pressed. The wiring is somewhat tedious but it is what it is. Here it is in action.

The $2 12V DC power supply can supply at least 10 modules so each additional ACC port only requires just the 4-channel relay module. Since only 3-channels are used per "new" ACC port, some wiring and space can be saved using 8-channel or 16-channel relay modules. These modules have similar less than $1/relay pricing. The relays in these modules start in the OFF condition so, like an AIU, the ACC port will be OFF when you power on the TIU/AIU.


The wiring of the multi-channel relay module is somewhat tedious to say the least. Another idea is to use a so-called bistable relay. On each trigger, a bistable relay alternates (toggles) between On and Off. So unlike the previous method which has 2 inputs (set and reset), the bistable method has a single input (toggle) which alternates between ON and OFF. So rather than pressing "diverge" to turn ON and "straight" to turn OFF, you press "diverge" to turn ON, then "diverge" again to turn OFF, then "diverge" again to turn ON, and so on. The "straight" button has no effect.

And here is is in action.

Perhaps obvious, but the downside of this method is you can't directly or absolutely set the Accessory to ON or OFF. You can only alternate between ON and OFF with each button press. This may be a non-issue since you might be watching the Accessory and can visually see it operating (or not). In any case, with the bistable relay, the relay itself starts in the OFF condition when you first turn on the AIU for an operating session.

As with the latching relay method, a single 12V DC power adapter can supply 10 or more bistable relay modules so the cost for each additional ACC port is less than $3 out-of-pocket.

The particular bistable relay module shown can be doubled up such that a single SW port can create 2 "new" ACC ports.

MTH AIU: make an ACC port from a SW port
Topics: 16   Replies: 16
posted on Feb 25, 2018:

Roll your own or purchased 4-wire 3-aspect LED signal heads typically use common "+" or common-anode wiring. Published circuits such as the reverse-engineered MTH timed-yellow method for 3-LED Red-Yellow-Green do not use the common "+" wiring.

The circuit can be modified with additional components. While the component cost is only a few dollars, the assembly and soldering can be tedious.

3-aspect timed-yellow circuitry also applies to PRR 7-LED style where the center LED is always ON. In both styles, the "+" DC supply to the LEDs has a single current-limiting resistor. For 12V DC operation, a typical resistor value for 1-LED-at-a-time heads is 1000 Ohms (3-LED-at-a-time heads 330 or 470 Ohms).

A low-cost "Delay ON" relay module from eBay can be used which in many cases can eliminate the need to turn on the soldering iron!

A signal head is typically driven by a 2-output occupancy detector such as the MTH ITAD or Lionel 153IR. The timed-yellow circuit provides the 3rd-output.

In any case, the occupancy detector must provide 2-outputs which even for the basic insulated-3rd-rail method will have a relay output with the "NO" and "NC" being the 2 outputs. Here's an example of the same delay-ON relay module providing timed-diagonal to a 3-aspect 7-LED 4-wire PRR-style head.

DIY 4-wire 3-aspect timed-yellow signal h...

O Gauge General Categories:

Electronics & Wiring (62)
   Alternating ditch light flasher for conventional control
Electronics & Wiring (62)
   Tortoise switch machine control using MTH AIU SW Port
Electronics & Wiring (62)
   MTH AIU: make an ACC port from a SW port
Electronics & Wiring (62)
   DIY 4-wire 3-aspect timed-yellow signal head
Electronics & Wiring (62)
   Servo control of MTH Z-controller transformer voltage, horn,...
Electronics & Wiring (62)
   Modifying a 99 cent servo for continuous rotation
Electronics & Wiring (62)
   Post war 3 rail relay blook
Scratch Built Rolling Stock (7)
   B&O and Other Equipment
Great Train Stations of O Gauge (35)
   From 4 MTH Banks to One Station PHOTOS RESTORED
Great Bridges of O Gauge (68)
   New metal bridge

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