Half Slips and Double Slips

snipped-for-privacy@mwfree.net said the following on 10/10/2005 09:56:

I would say that so long as you build the slip accurately and have consistent wheel back-to-backs a double slip is no more trouble than any other item of pointwork - it is just a set of crossings and switches in a smaller space!

Depends on which gauge you are working in. In OO you will find single or double slips very difficult to check properly. I certainly avoid them like the plague. I had two sets on my last layout because they were prototypical (it was an actual location) and they took more maintainance than the 60 other sets of pointwork on the layout. Two turn outs back to back will do everything a slip does ten times better, so unless you have to put them in my advice is don't. In P4 things are a bit easier as the narrower check rail spacing will give a bigger margin of safety but even there I have seen people struggling to get total reliability.

My current layout avoids slips (also an actual location -- the HR avoided the full size ones) and I spend zero time on turnout adjustment.

Alistair Wright

Sounds as though it is back to the drawing board, this is similar to all the other comments that I have heard. I can get around the problem I have by laying the junction out differently but I will lose out on flexibility, but I would prefer that to unreliability.

Kevin

"Alistair Wright" wrote

We seem to have a real down on d/slips in this country, but the French seem to make them work perfectly well. If ever you get to Paris take a look at the Gare du Lyon - it's probably host to more slips than the entire British network.

John.

But what did your prototype (or Company) do ? thats what *should* matter IMHO.

In OO we have a fiddle yard with 14 double slips - no problems at all for several years and exhibtions.

I've got a double and a single in my station throat and never had a derailment. I took time getting them level before fixing them down though. Not true on regular points I've rushed though! Rob

snipped-for-privacy@mwfree.net said the following on 10/10/2005 11:21:

Just out of interest then, what sort of problems are people getting with slips? Are we talking about stock falling off the RTR Peco ones, or people's inability to handbuild to a sufficient standard? If the former, it should be returned as not fit for purpose, and if the latter, then build more to get the practise in! As I mentioned before, and other people have confirmed, a slip is not intrinsically unreliable, whether single, double, outside or Barry.

asking the neighbour if I can pinch half his loft isn't an option. The choices open to me are to use a double slip and hope that I don't get derailments, use convential points but not get access from all routes into a bay, redesign the layout, extend the house, scrap oo gauge and go for N gauge. The second option seems preferable at the moment.

Kevin

The only think I had trouble with when fitting a double slip on my father-in-law's layout was trying to remember the correct position of the rails to route the train on the right track - but that was down to the little grey cells not functioning reliably, and not the reliability of the slip :-)

On a serious note, the only issue I know of is when using electro-frog versions of these slips. I think they need to use a change over accessory switch or two so as not to cause shorting of the track feeds. This is assuming you are using normal DC feeds. If using AC then I would of thought it wouldn't matter ?? (I'm sure someone will correct me if I'm wrong)

Malcolm

If by AC you mean DCC, then it does matter and the solution is exactly the same as for DC.

Mark Thornton

To you maybe - only you know the answer to that, my view still stands, what would the prototype do ? If you have limited space you have limited options.

Why hope ? - if you track is laid and adjusted carefully there is no reason you should get derailments - on any of it,

Why does your bay need access to all routes ? could you use a connection in the fiddle yard and run wrong line onto the layout to give the same ability but without the slip / crossover ? Could the bay have limited access thereby forcing a shunt move ?

Its often said that you should choose the model you like and then choose the scale you can model it it ....

"John Turner"

When I were a kid back in the 1950s and 1960, almost every UK station it seemed had at least one slip, usually a single. They were as common as muck. They were also used quite a bit in goods yards and loco sheds.

Heck, Ventnor goods yard and station on the I.O.W. had at least two, possible three slips in that small space. The bay platform at Havant had at least one double slip at the end of the run around for the Hayling Island loco plus there were several others on the main. There were slips everywhere.

-- Cheers Roger T.

Home of the Great Eastern Railway

"Roger T." wrote

Aye, but in those days we also had railwaymen who knew how to maintain them!

John.

The French, and indeed other continental railways love them- Lyon Perrache has ladders on both ends of the station which use several, whilst most major termini will use a string of them (though often with quite severe speed restrictions- the 20kph one at the exit to St Lazare comes to mind). There was a lovely photo in the IRSE journal a few months ago showing a station (on NS,IIRC), with a six track layout at the approach to a station with ladders of double slips allowing interchange between all tracks in both directions- looked like the sort of thing that would have adorned the Graham Farish advert on the back of Model Railway News 30+ years ago. One thing that is noticeable about French pointwork, at least, is that the 'check-rail' is more correctly a hefty piece of 'L' section, reinforced with fillets, and noticeably higher than the running rails. Several railways in the UK (the GWR amongst them) used to use a single slip in conjunction with a normal turnout to provide a trailing crossover with a trailing access to a yard. Brian

In which case it's time to post a positive. My layout is based on a Swiss based prototype as a result of which I have 5 or 6 Peco code 75 double slips. The majority are in daily use (one is the main exit from the fiddle yard) and perform without problem. I was warned about problems with slips when I went for this track plan but my experience is that it's not a problem. Some out of date photos at

Nigel

In message , Paul Boyd writes

In my experience, the radius of the slip roads on the Peco slips is far too small.

I looked back through all my Peco catalogues, and they give no indication of what the radius is. I wonder why?

You can actually calculate it, however. The chord length (straight line distance from one curved switch blade to the other on the same rail) is

105 mm, and the angle of the curve is 12 degrees. Simple trigonometry (draw an equilateral triangle with the chord as one side, and the radius from both ends of the chord to the centre of curvature as the other two sides, then draw a line from the centre to the middle of the chord) shows that the radius is 52.5 / sin 6 degrees, i.e. 502 mm. (or, if you like, 19 3/4 inches).

When used with large-radius points, this radius is rather sharp, to say the least, and is very much smaller than the minimum radius on my layout, which is 3 feet.

On 10/10/2005 19:22, Jane Sullivan wrote,

...is an oxymoron!

Flippin' 'eck! If these are the beasts that have given slips a dodgy reputation, I'm not surprised with that radius. That's train set stuff!

A far more sensible radius.

Perhaps it's just when Peco DSPs and SPSs are used on British layouts that they misbehave?

OTOH I bought an older second-hand Peco code 100 DSP for my fiddle yard and rarely got a complete train across it. As at that time I still believed in magic I bought a replacement new, even though I couldn't see anything wrong with the first one. The replacement worked much better, perhaps 99%. The two DSPs somehow looked different so I put them side by side and Wow! The flangeways on the old one were noticably wider! After that I actually began to think - 99.5% of wheels pass through without problems - could it be that those 0.5% of wheels were somehow different? - out came the vernier callipers to measure back-to-back wheel dimensions - I quickly found that around a third of all my wheelsets were outside tolerances, and 1-2% of those were over a millimeter outside tolerances and quite a few were wobbly, out of round, had damaged flanges .... etc. Some just had so much crud on the treads that they were effectively almost flangeless. Nowadays I only allow metal (rimmed) wheels on the layout and while my checking only goes as far as a quick eyeball of b-to-b, clean treads and a wheel spin to check for concentricity, I can't remember when I last had a derailment anwhere.

Regards, Greg.P.

snipped-for-privacy@mwfree.net wrote in news: snipped-for-privacy@g44g2000cwa.googlegroups.com:

...

Notwithstanding my recent problems vis a vis installing a point motor see elsewhere) I have 2 double slips on my current layout togther with a single slip. All are Peco commercial products. Additionally only the single slip is new, the double slips have been recycled from my last layout.

I have no problems with stock derailing or any nonesence like that. Whether the stock is Hornby, Bachmann, Lima or even kit built with Gibson finescale wheels (I do use a OO society back to back guage though on all my wheels).

Don't be put-off they're great space savers.