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Dual Gauge Turntables


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  • RMweb Gold

First my apologies if I have this is in the wrong section but I couldn't find a specific 'broad gauge' forum.

 

A question in two parts...

 

I understand that in the early days a turntable would be used at the end of a terminus station to both turn an engine and act as a point to return the engine to the front of a train (see pic).  If correct would this practice have continued in to dual running era?

If the practice continued, how would 'narrow gauge' engines be turned, would I be correct in assuming they were only ever turned ~150+deg to only ever align with the additional 'narrow' rail?

 

Thank you for your help.

 

John

bgtt.png

Edited by John Hubbard
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  • RMweb Gold

Following that logic the lines entering the TT would need to 'split' before the TT in order to have the rails central as per image?  This affecting the BG shared line only, the NG line can be slewed across.

Thank you for your help, it's much appreciated. :D

bgtt2.png

Edited by John Hubbard
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21 minutes ago, John Hubbard said:

Following that logic the lines entering the TT would need to 'split' before the TT in order to have the rails central as per image?  This affecting the BG shared line only, the NG line can be slewed across.

Thank you for your help, it's much appreciated. :D

bgtt2.png

That's it.

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There was a dual gauge (broad and standard) turntable in Devonport Dockyard until rescued by the GWS and is now at Didcot, but restored in bg only.

The dual track was in one direction only, by adding sg after 1892, to allow the table to be repurposed once bg had been discontinued. All tracks were central on the axis.

Full details here: http://www.gwsbristol.org/gwsturntable.html

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There's a lot of excellent logic, to say nothing of Australian practice*, put forward here but only @pb_devon's example of actual Great Western (or rather, GW constituent) practice, and that's a wagon turntable.

 

So, from a standpoint of ignorance, I ask, what BG branches were originally built with engine release TTs, and did they actually need TTs by SG days, when they would mostly have been worked by tank engines, or so I understand? I believe the Board of Trade prohibited tender-first running over distances of more than twenty miles; whilst there were some long GW branches, were many of those built to BG among them? And were any such branches regularly worked by trains of both gauges?

 

Really, I'm wondering if, with apologies to @John Hubbard, the question isn't a red herring?

 

*Please excuse my drawing a distinction between logic and Australian practice; I cite the mess they got into over gauge as my justification.

Edited by Compound2632
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  • RMweb Gold

Without going through all sorts of sources it is difficult for me to positively state one way or the other how many broad gauge branches on the GWR had engine release turntables.  Henley is undoubtedly the best known example and it went straight from broad to narrow gauge in 1876 without a mixed gauge interlude.  However there is the open question  - at this stage - about what happened in various engine sheds, for example Westbourne Park served a mixed gauge railway into Paddington for many years and while there might have been (I think) different broad and narrow gauge sheds were there separate turntables?  and of course it wasn't unique in serving both gauges. The Crossrail digs at Westbourne Park uncovered separate broad and narrow gauge pits but the turntables changed over the years at one time there were two and by 1889 there appears to have been one serving the short shed building which was probably the broafd gauge shed as teh longest pits were narrow gauge according to photos from the dig.

 

A Has anybody got a copy of Lyons' second book dealing with thh various closed sheds that went prior to 1948?

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  • RMweb Gold
4 hours ago, Compound2632 said:

There's a lot of excellent logic, to say nothing of Australian practice*, put forward here but only @pb_devon's example of actual Great Western (or rather, GW constituent) practice, and that's a wagon turntable.

 

So, from a standpoint of ignorance, I ask, what BG branches were originally built with engine release TTs, and did they actually need TTs by SG days, when they would mostly have been worked by tank engines, or so I understand? I believe the Board of Trade prohibited tender-first running over distances of more than twenty miles; whilst there were some long GW branches, were many of those built to BG among them? And were any such branches regularly worked by trains of both gauges?

 

Really, I'm wondering if, with apologies to @John Hubbard, the question isn't a red herring?

 

*Please excuse my drawing a distinction between logic and Australian practice; I cite the mess they got into over gauge as my justification.

If the question is a red herring it isn't deliberate, I'm genuinely trying to understand the GWR BG approach, and I do appreciate the contribution thank you :)

I know from the few books I have that TT engine release was in practice, but I can't find the point at which it ended, but it is certainly evident during the BG period, I guess the question is would it be present in a station during dual gauge?  If the probability is that a station engine release during dual gauge would be via points that would at least address one issue for me.

However, I do still need to turn engines due to the BoT prohibition.  The period I'm interested in modelling is up to and including the very first years of the dual gauge for no other reason than I can run the early fascinating BG engines and early standard gauge stock.  I guess I'm trying to have my cake and eat it.

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  • RMweb Gold

To reply to the Stationmaster:

Yes Lyons & Mountford Sheds V2.

Paddington is on page 137 and covers 1845 only. 17 or so locos.

Broad gauge only.

( I only bought it for its Taff Vale Shed Coverage esp. Penarth Dock).

How can I help?

Edited by BMS
rdp is not esp.
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4 hours ago, Compound2632 said:

 

*Please excuse my drawing a distinction between logic and Australian practice; I cite the mess they got into over gauge as my justification.

But you would be pleased to know that the Victorian Railways once used inside chaired track, because the engineer previously worked for the Midland Railway.

 

Some photos of inside chaired double head track can be seen here.

 

http://pjv101.net/film_bw/pjv00097.htm

 

Most of the early mainlines built by the state government, where of a very high standard and double track from the start.

 

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  • RMweb Gold

Taking in to account the feedback, I've shifted the TT from the end of the platform, but as I still need to turn the engine I've added a spur leading to a TT.   

It's at this point when I felt like a cyclist with wheels dropping into tram tracks when as soon as I added a station and good shed a prototype came to mind.

My challenge will be making it sufficiently different t so as not to be labelled yet another...   

I'm hoping with the scenery and the obvious use of dual gauge I can create the differentiation, perhaps even removing the train shed will help with this although they are a nice early feature.

Noting the diagram is showing the P4 track and not the BG (not an option on Anyrail), is there anything else I should be doing do you think?   All suggestions welcome.

Morton.png

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I am actually rather surprised at the solutions that have been shown for dual gauge turntables. My local model engineering society had a neat solution for it's 5 inch / 7 1/4 inch turntable that was something like this if you will excuse the quick paint job:

 

1816878750_dualgaugeturntable.png.897c745e5b2ee94caaecb0878970b5fe.png

 

The broad gauge rails were continuous, and the check rails ensured that the narrow - or standard gauge wheels took the right route. No messing with any extra rails outside the turn table, no moving parts on the turntable and no matter which way you turned it the rails would line up.  It worked well and I am surprised that it was not based on full size practice.

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Some pictures from the museum in Golden, Colorado.  Afraid the gauges are standard and 36".

 

The turntable is not lined up with the approach roads.

 

 

Golden5559.jpg

Golden5561.jpg

IGolden5562.jpg

Edited by BR60103
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  • RMweb Gold
18 hours ago, John Hubbard said:

Taking in to account the feedback, I've shifted the TT from the end of the platform, but as I still need to turn the engine I've added a spur leading to a TT.   

It's at this point when I felt like a cyclist with wheels dropping into tram tracks when as soon as I added a station and good shed a prototype came to mind.

My challenge will be making it sufficiently different t so as not to be labelled yet another...   

I'm hoping with the scenery and the obvious use of dual gauge I can create the differentiation, perhaps even removing the train shed will help with this although they are a nice early feature.

Noting the diagram is showing the P4 track and not the BG (not an option on Anyrail), is there anything else I should be doing do you think?   All suggestions welcome.

Morton.png

Have a look at Moretonhampstead track layout because I think it unlikely in some 19th century periods that access to the goods shed would be via a facing point in the passenger line.  Quite likely to havre been like that when the line was built but when the narrow gauge rail was added it was probably altered to eliminate that facing point.   incidentally the release crossover would probably be nearer the platform line stop block in order to create the maximum possible length of train for an engine to run round and there would ba trap point (or wheel stop) of some sort on the loop line where it joins the main line.  the goods shed sidng would also probably have a wheel stop as can be seen on the broad gauge track layout at Didcot.

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56 minutes ago, The Stationmaster said:

Have a look at Moretonhampstead track layout because I think it unlikely in some 19th century periods that access to the goods shed would be via a facing point in the passenger line.  

 

Here's the Ordnance Survey's impression of Moretonhampstead in 1885, when the line was still broad gauge; the goods shed road runs directly into the passenger line: https://maps.nls.uk/view/136635962.

 

By 1904, the loop has been lengthened, with a crossover beyond the train shed, and the goods shed line runs into the loop, via a plain crossing over the passenger line: https://maps.nls.uk/view/106004264; on the other hand, the shed road, which had been connected to the passenger line via a crossing (probably a slip) over the loop, is now connected only to the loop. Plus an extra siding. There are presumably some traps that were beneath the surveyor's notice.

 

As the gauge conversion was done over a weekend in 1892, it seems unlikely to me that the layout was changed then; I suppose it must have been improvement work at some point in the following decade.

 

The small turntable in front of the engine shed had been removed by 1936: https://maps.nls.uk/view/106004267.

 

I can't resist posting this very nice photo:

 

image.png.440791bae8ae12840646d53b5c2ae680.png

 

[Public Domain, https://commons.wikimedia.org/w/index.php?curid=15282237]

 

The Wikipedia caption says c. 1909 but not before 1905 but my understanding of Great Western carriage liveries tells me that 1909 is the earliest possible date and it is perhaps several years after - the brown or maybe lake carriages have been in service for a good while, given that their white roofs have gone to as dark a grey as those of the two carriages still in pre-1908 livery; their varnish has dulled a bit, too. (I read that brown started to be applied in late summer / early autumn 1908, with some carriages still being turned out in chocolate and cream to the end of the year; the photo is clearly high summer; if it was 1908, the brown carriages would have fresh white roofs! )

Edited by Compound2632
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23 hours ago, Compound2632 said:

As the gauge conversion was done over a weekend in 1892, it seems unlikely to me that the layout was changed then; I suppose it must have been improvement work at some point in the following decade.

Or in the period running up to the gauge conversion. quite often preparatory work was undertaken to include narrow gauge into parts of broad gauge layouts in order to facilitate the changeover, which primarily concerned the miles and miles of plain track. For pointwork, it is simpler to add the narrow gauge rail and timbering before conversion than it is to actually convert a turnout on the ground.

 

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12 minutes ago, jim.snowdon said:

Or in the period running up to the gauge conversion. quite often preparatory work was undertaken to include narrow gauge into parts of broad gauge layouts in order to facilitate the changeover, which primarily concerned the miles and miles of plain track. For pointwork, it is simpler to add the narrow gauge rail and timbering before conversion than it is to actually convert a turnout on the ground.

 

I can see that, and it does make more sense that the layout would be changed as part of the conversion rather than later. Presumably this entailed relaying most of the station area with transverse-sleepered track, even though the plain line remained baulk road - assuming it was in the first place?

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13 minutes ago, Compound2632 said:

 

I can see that, and it does make more sense that the layout would be changed as part of the conversion rather than later. Presumably this entailed relaying most of the station area with transverse-sleepered track, even though the plain line remained baulk road - assuming it was in the first place?

Did the management of the GWR of 1892 curse Brunel? All this extra work they had to pay for.

 

The LNWR board must have had a good laugh! The LNWR had earlier spent quite a bit on legal challenges, making sure they never had a break of gauge station with the Broad Gauge.

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18 minutes ago, Compound2632 said:

 

I can see that, and it does make more sense that the layout would be changed as part of the conversion rather than later. Presumably this entailed relaying most of the station area with transverse-sleepered track, even though the plain line remained baulk road - assuming it was in the first place?

Possibly, although as there aren't many photographs of gauge conversion, there isn't much to go on.

 

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5 minutes ago, kevinlms said:

Did the management of the GWR of 1892 curse Brunel? All this extra work they had to pay for.

 

To say nothing of the additional capital outlay when the BG lines were first built and the liability of the baulk road. Ahrons explains why sandwich frames remained in vogue on the Great Western long after everyone else had gone over to solid plate frames: they provided the flexibility and springiness that was lacking in the p/way. He says the old drivers used to reckon their engines one or two coaches better on transverse-sleepered road than on the baulk road. And that was well after the piling had been removed / sawn through, which was done very early on. (Ahrons was a Swindon Loco. Dept. apprentice in the 1880s so had first-hand experience.) I expect they were already cursing him in 1866, when Gooch as Chairman went cap-in-hand to Disraeli pleading for nationalisation.

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8 minutes ago, kevinlms said:

Did the management of the GWR of 1892 curse Brunel? All this extra work they had to pay for.

 

The LNWR board must have had a good laugh! The LNWR had earlier spent quite a bit on legal challenges, making sure they never had a break of gauge station with the Broad Gauge.

Very probably, but the writing had been on the wall ever since the decision by the Gauge Commission favouring 4' 8.5" gauge, and removal of the broad gauge had started a good twenty years earlier. The original decision to adopt broad gauge was sound enough at the time, but what could be argued as technical excellence was swamped by the sheer quantity of standard gauge track that was built. Shades of Betamax and VHS many decades later.

 

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