Wiring for Block detection

[matt1471]

Do I include the points in the blocks?

If I do, am I advised to add droppers to the points as well, or just rely on the rail joiners?

[TimberSurf]

Simple yes. Else the train will be 'lost' when it is over the point

[RFS]

It depends what you are trying to achieve with the monitoring. I run Traincontroller from RR&Co and the recommendation there is not to include points in monitoring. Trains move from block to block and knowing which way the turnouts are set allows TC to keep track of where trains are. My station throat has some complex point work and TC has no problem with there being longish sections of pointwork between monitored blocks. Trains do not usually come to a stand on pointwork, and are unlikely to be wholly contained within a single point, so the adjacent block(s) will indicate the occupancy. Apart from anything else monitoring all points can become quite expensive!

[matt1471]

So if I'm 'not' to include the points in my detection, would I need to wire these to a separate power bus?

I'm only using the detection to show when a block is occupied by a train and to maybe then prevent points being set 'illegally'

[RFS]

No need for a separate power bus for the points. But you will need to isolate the points from the detected sections with insulated rail joiners so that trains passing over the points do not activate the detection. This assumes that you are using a detection method that uses occupancy detectors via the track feed. If you are using some other method (eg reed switches etc.) then you may not need IRJs. But occupancy detectors are the most reliable.

[matt1471]

Surely I will need to supply the point with power and give each point it's own dropper if I'm to isolate the point from the track that requires the detection?

I'm using DigiRails occupancy detection - so current based detection.

For a simple length of track leading into a point and having two sidings for example would require 3 blocks. If I'm to isolate the point, how would it get it's power?

Thanks
Matt

[TimberSurf]

That's why I humbly suggested that the point should be in the block leading to the point, then if the lead up to or if either side of the point are occupied, neither of the two sidings should be allowed to enter into the point.
Thus only when the track before and all parts of the point are clear should the block show clear. Personally, I would add 3 inches past the point on each leg to ensure a train is not parked just short of the frog, meaning a corner might be hit by a passing train on the other side.

[RFS]

Surely I will need to supply the point with power and give each point its own dropper if I'm to isolate the point from the track that requires the detection?

I'm using DigiRails occupancy detection - so current based detection.

For a simple length of track leading into a point and having two sidings for example would require 3 blocks. If I'm to isolate the point, how would it get its power?

Thanks
Matt

You simply provide DCC droppers to the points. With DCC it's often recommended that you have a dropper on every piece of track, and it's what I do with my layout. For detection on the simple length of track that you describe, then Timbersurf's suggestion is fine. It's not so easy though with complex point work forming a station throat.

As far as detecting whether a train has fully entered a block, as Timbersurf has suggested, then you will need resistor wheelsets on at least the last vehicles for this situation to be detected. I do this too, not to aid automation, but simply to detect coupling failures causing vehicles to be dropped.

[matt1471]

Thanks for the advice all.

I was thinking about adding droppers to each point, just to maximise their connectivity and improve running and think I'll probably need to if I'm going to use block detection.

I've attached my layout plan. I think the location of the blocks is quite self explanatory, but a couple do you have some crossovers in the middle of them.

[RFS]

How are you going to use the detection, and in particular what software are you planning to use? Are you going to be using some form of automation to drive trains, as the software will need to know where in a block a train is so that it can stop the train in the right position. Having turnouts in the middle of a block will cause a lot of confusion.

Also detection relies on current draw, usually the loco, so once it leaves a block that block becomes undetected unless you have fitted resistor wheelsets to the vehicles of the train.

Plus you need to give some thought to train lengths and block lengths. Trains that are longer than detected blocks raise various issues etc.

[matt1471]

I'm using JMRI and only using the detection in it's simplest form. I just want it to mimic on a control panel when a section has something in it (the loco) I'm not fussed about the coaches/stock.

No automation. The most I will probably get JMRI to do is to stop any point movements that would allow a train to run into a section that is occupied.

[RFS]

In that case it's your choice as to how granular you want to be. Where you have the issue of crossovers you could simply treat the track there as single blocks with the turnout in the middle of the block. But you will need IRJs on both diverging rails so that a train passing on the adjacent track doesn't turn the indicator on.

Plus I would suggest looking at having resistor wheelsets (at least on the last vehicle) so that a long train spanning two blocks keeps both detectors on.

[matt1471]

Doesn't need to be exact...I think I've allowed enough detection sections to split the blocks around the crossovers so shouldn't be an issue.

I think if I included the entrance to the point within a block, then I can make most of it work for what I want it to.

Will look into adding the resistors when i get that far!