John Purbrick (at long last) brought in a cab constructed for radio operation. It was able to run a train! Note rechargeable batteries at the bottom, metal strips at the sides which contact the user's hand (no need for an "On" switch), and case borrowed from Cab 6. The large green component that looks like a resistor is actually the inductor that's part of the step-up voltage converter. It seems to run for about 3 hours on a full battery. Most of the power goes to run the LCD backlight. The cabs feature bidirectional communication, with data from the server being used to place text on an 8x2 LCD, and run signal lights and a beeper.

This is the "base unit" for the radio cabs. A circuit board from the cab construction program was sacrificed to place the receiver and transmitter modules on, wired back to the processor on one of our general-purpose project boards. The transmitter is the smaller of the two modules, and the receiver is the larger one. Each has its own antenna, the cylindrical devices at the bottom. The design issue that remains to be determined is how many units can run on one channel. All the boards communicate at 433MHz, so transmitters must be switched on and off at precise times. It's also not clear what rate we can use to send digital data. At present the system uses 13KB, but it can probably run faster. We think we can get "several" but not "many" units working at once.

In addition to his other work while he's been away, David Lambeth cast some switch stands. They are very small and delicate. Here is the first one, installed in F-yard. The post carrying the flag is .020 inches diameter. Although we've built operating switch stands in the past, this one doesn't move. We also had a visit from computer, business and academic veteran Dr Edward Fredkin.

	In order to prevent the points of this turnout from occurring on a bridge, a gantlet section was installed. This is based on a prototype in Bellows Falls VT.
	The installation of a new signal starts with "Dig we must".
	The circuit board is in place and the unpainted signal installed. The signal heads and base were cast in polyester by David Lambeth, who presented us with a bag of them.
	It lights up!
	All done.
	New member Paul is scraping down some second-hand passenger cars. They're tough--the car shells are made from aluminum extrusion.
	Returned (briefly) member David installed a fence, and new member Chloe put in some weeds beside it.
	She made a driveway too.

Michael's latest in freight car assembly. This time it's an Intermountain cylindrical covered hopper kit.

The "Chesapeake" is the Chesapeake & Lake Erie, the railroad of the North Shore Model Railroad Club, where we have many friends.

	The brake components are very small and precise.
	There are also roof hatches. Note the brackets for attachment of the roofwalks.
	Brake components partly concealed by end ladders.

First progress report for almost two months! It's shocking.

	Michael Stunes has been assembling a couple of Red Caboose brand freight cars. He says there are plenty of fiddly parts, but he's not afraid.
	Here's one of them.
	And here's the other.
	Meanwhile Bill Onorato has been installing people, scenery and details around Madlinger Chemical.
	Perhaps it's time for a break, or can it be that Madlinger Chemical's employees are a little averse to work?

	Last week's operating session led to a suggestion that for two operators to work together at F-yard, they need a car-order box each. Such a box is under construction. Yes, we have a fine collection of clamps.
	The new car card box completed and installed, with new movable labels and a barrier to keep the labels from getting pushed off by people brushing against the fascia.
	John M added new I-beams to the Pessim Steel warehouse.
	For no very good reason, here is a picture of a train on the crossing at Middle Heights.

	The Madlinger family--our alumnus Adam, and his parents Cathy and Gary--paid us a visit, and as usual when they drop in, all three of them got to work. Here's a group photo.
	They installed a signal tower and a small section of rock face adjacent to their stupendous rockwork from two years ago. (See April 7, 2007.)
	Then there's new gravel around the White tower restaurant.
	And people on the platform at Berkmannville.
	We had a four-person operating session to try and work out the issues that were brought up by the RailRun operation two weeks ago. Malcolm Laughlin made a visit to share his expertise. It generally went more smoothly. Paperwork is part of running a railroad!

	The same computer runs both our control system and our website, and it suffered a shutdown of unknown cause today, which pretty much put us out of business. Fortunately James Knight made an appearance and got it working again, then spent a long time doing mysterious things with Linux. James remarked that our two main computers are "getting pretty long in the tooth".
	John P installed new labels on the car card boxes, dealing with the complaint (from the RailRun session) that it's hard to identify locations on the railroad.
	There's also a new box for cars at destinations within F-Yard. It's attached to the fascia with screws rather than VelcroTM because we couldn't find the VelcroTM when we needed it.

	John M worked on the steel warehouse in East Berkmannville.
	Quentin has installed lighting in Ken Tyrell's subway station. He used cold-cathode fluorescent tubes from a broken LCD panel.
	This is how it looks, with the wires glued up out of sight, but the glue's drying, hence the clamps.
	John P has made a whole bunch of new industry shipment pockets, using David Lambeth's pattern.

We now have revenue service to East Berkmannville! And the card pockets are a little narrower.

This weekend we also hosted a RailRun session, where experienced operators from all over the area came to operate on our layout. Pictures are available under the link above this post.

	We had some trouble with Block Card 10. Quentin is fixing JP's fix to this item.
	Christina and her friend Cydnie have a talent for producing trees--the forest is growing!
	Quentin helped out too.
	Here they're drilling the holes for planting.
	Quentin rigged up a nozzle for the vacuum cleaner to remove dust without damaging the vegetation.
	Finally he simply sprayed the whole area with dilute India ink.

Quentin also added a feature to the system that causes trains whose speed is brought to 0 to be electronically braked using the freewheeling diode on the block cards. Some locomotives now can stop within an inch when running at full power.

If we showed a picture of the coding process, it would just look like a guy at a computer, but we're showing pictures of our models, so why not show Quentin's work?

Index: tmrc/railserver/picnet/BlockController.java
===================================================================
--- tmrc/railserver/picnet/BlockController.java (revision 333)
+++ tmrc/railserver/picnet/BlockController.java (revision 335)
@@ -5,6 +5,7 @@
 public class BlockController extends CardController implements EventReceiver
 {
        Block[] blocks = new Block[8];
+       int oldspeed = 0;

        public int getTypeId()
        {
@@ -50,9 +51,22 @@
                if(cardPos == -1)
                        return;

+               boolean direction = b.getDirection();
+
+               // E-braking. If the block is at 0 but assigned, invert
+               // the polarity so the freewheeling diode will stop the train more quickly.
+               if ((b.getOwner() != null) && (b.getSpeed() == 0) && (oldspeed != 0)) {
+                       direction = !direction;
+
+                       // Re-enter after a delay to reverse back
+                       Age.installDelayedEvent(new RealEvent("setSpeed", null, b), 500, this, false);
+               }
+
                int[] data = new int[] {
                        cardPos,
-                       b.getSpeed() & 0x7f | (b.getDirection()?0x80:0x00)};
+                       b.getSpeed() & 0x7f | (direction?0x80:0x00)};
+
+               oldspeed = b.getSpeed();

                sendPacket(BLOCK_SEND_SPEED, data);
 //             System.err.println("Setting speed of "+b.card+" "+b.cardPos);

	A new doohickey for a Tortoise(TM) switch machine! To replace one that, um, unfortunately became lost.
	Experimental radio cab circuits. Gee whiz, this thing may actually work.
	Greenery in Middle Heights.
	Trackwork in East Berkmannville is complete! But now it all has to be wired.