7mm Yorky D's LT - Wagonery tales from the Met.

[Yorkshire Dave]

we expect to see the fresnel rings on the lenses as well, just doesn't look complete without them

Oh dear, how very remiss of me . Banished to the back of the classroom .

As a thought I wonder how you could achieve the Fresnel rings on the 4mm dia clear acrylic rod.

Interesting as the Fresnel lens is there to concentrate an incandescent light beam - whereas the LED already achieves this in this scale. To be honest I've never looked for the Fresnel effect on today's LED colour light signals and traffic lights.....

 

[simond]

Non-LED traffic lights definitely had Fresnel lenses, or at least, had concentric rings on the lens face.

I’m equally sure that the so-called temporary LED lights that have blighted the route from our house to the rest of the world for the last few months don’t.

There is a very nice Fresnel lens assembly from a lighthouse in the maritime museum in Paimpol, which is a nice part of th3 world.

Atb
Simon

 

[Yorkshire Dave]

Rail Gap Indicator..... completed

On the left is a you would normally see them and on the right when the next section of conductor rails have been isolated.... it appears orange here but is red on my other monitor. A bit of tidying up of the supports required.

The post is made up from square copper tube from scrap box and the base plate is scrap brass etch. The post will be painted a concrete colour.

 

[Yorkshire Dave]

I've finally made one - a working tripcock..... made up from a piece of square brass tube with a few holes cut into it and some scrap brass etch and tube. Operated by levers and linkage within the tube.

 

[mickoo]

Lunacy

Love it

 

[Ressaldar]

a truly pivotal moment, great stuff

kind regards

Mike

 

[Chris Veitch]

I've finally made one - a working tripcock.....

As one who is fascinated by but very ignorant of the Met and its ways, errrrrrr... what is it and what does it do?

 

[Yorkshire Dave]

As one who is fascinated by but very ignorant of the Met and its ways, errrrrrr... what is it and what does it do?

In short it's a train stop device - an LT version of a SPAD. An actuator arm is located on the train's truck/bogie and when this hits the raised tripcock it applies the train's brakes. There's more about it here.

 

[Overseer]

In short it's a train stop device - an LT version of a SPAD. An actuator arm is located on the train's truck/bogie and when this hits the raised tripcock it applies the train's brakes. There's more about it here.

Isn't the tripcock the part mounted on the train that hits the 'train stop device' and lets air out of the brake pipe? Or air into the brake pipe if it is a vacuum system, although I don't know if the Met or other railways used vacuum tripcocks. Most intensive urban railways around the world used an electro-pneumatic version of the Westinghouse brake to cope with the frequent brake applications.

Nice model btw.

 

[Yorkshire Dave]

You're correct, the 'tripcock' is the device fitted to the train and the 'trip arm device' is on the track.

They were around in 1914 (District Railway) and I came across this LURS article Dead Man's Handles and Tripcocks.

The Met used both Vacuum and Air brakes. In crude terms steam hauled stock was vacuum braked whereas multiple units were either vacuum or air braked, which in turn made any remarshalling of these tricky. The Met Bo-Bo has two tripcocks on each side mounted on the truck/bogie - one for vacuum and one for the air brake and the steam locomotives had one tripcock on either side for the vacuum brake.

 

[simond]

Thanks Dave,

Very interesting article.

Atb
Simon

 

[Yorkshire Dave]

The tripcock operating device has now acquired ramps and a coat of paint.

This is how it would appear on the track. The top of the box is just proud of the rail head and well below the top of the outer conductor rail.




An attempted shot of the simple mechanism - all made up from brass from the scrapbox .

 

[James Fibbens]

That's impressive and very dedicated! It'll look good when installed on some 4 rail track.

A small technicality - I think the Tripcock is on the rolling stock. What you have there is known as a train stop I believe.

 

[Heather Kay]

So, Dave, the plan is the trip will cut power to the track and stop the loco/train like the real thing?

 

[mickoo]

So, Dave, the plan is the trip will cut power to the track and stop the loco/train like the real thing?

Don't tempt him

 

[S-Club-7]

So, Dave, the plan is the trip will cut power to the track and stop the loco/train like the real thing?

A more elegant solution would be for the trip to tell the DCC chip to stop the train complete with all the relevant sound effects.

 

[Yorkshire Dave]

A more elegant solution would be for the trip to tell the DCC chip to stop the train complete with all the relevant sound effects.

Yes, the tripcock 'thwock' would be nice.

So, Dave, the plan is the trip will cut power to the track and stop the loco/train like the real thing?

If only, I'm sure it can be achieved.

 

[Engineer]

I agree completely with the elegant contemporary approach of post 396. There could still be an interesting challenge to make a working electro-mechanical solution that relies on physical contact, harder as the scale shrinks and diminishing equally in reliability and value.

There is evidence of a successful model demonstration of the post 394 solution, with control external to the vehicle, described in articles in the Model Engineer in 1939. It included a Met loco, demonstration plank with signal and a form of mechanical trainstop, and a master controller with deadman. The train stop could be raised and when struck, would bring the loco to a halt by cutting the power to the track supply. Scale was 1/24 which means that Gauge 0 solutions are not completely out of reach.

 

[oldravendale]

Dave - you are completely out of your tree, but in a nice way. I am in awe and admiration.

Have a great Christmas - and to all other subscribers to this erudite organ.

Brian

 

[simond]

Apropos our discussion at Reading, I have obtained the necessary hardware for a basic noise-maker to accompany your trainstop and my AWS ramp, but it is very basic, it’ll make a noise (I still don’t have a “thwokkk” sound, though I have found a candidate) if the signal is against the train, and the train has triggered it. Similarly, my AWS will ring or hoot according to the state of the signal input when triggered. (I’ve not got decent sounds for these, if anyone can help...)

I haven’t done the sketch yet, it’s a task to follow tomorrow’s goose... or not, maybe Boxing Day... but it’s pretty easy - it can cut the power to the track if so desired, but that’s not a great solution with DCC.

It’s a bit more challenging is to sort out the hardware and sketch for a DCC version that can issue a Stop command, and I haven’t considered that at all at this point. It’s particularly challenging if you have more than one powered unit - you only want to stop the errant unit, not all the others - so how does the trainstop “know” which loco to issue the command to? It CAN be done, there are means to interrogate the decoder of the loco in a given section, but this is not a task for tomorrow!

And not with the five quid I’ve invested!

Season’s Greetings
Simon