Grovenor Posted July 5, 2011 Share Posted July 5, 2011 If, as I think was said, that we are talking about the second half of the 20th century, then the aversion to facing points was much less than in earlier periods and there were lots of facing points in use that could not be classed as "absolutely necessary". And from a risk viewpoint the hazard presented to expresses on the up and down fast by a freight pulling across its path at 15mph or reversing across its path at, probably a bit less would be near enough the same. in either case one of the fast lines would be crossed in opposing directions and one in similar directions. The signalling arrangements to stop trains on the fast lines would be the same in either case. The general hazard from something going wrong with the freight would be a bit higher when propelling. So as I see it a facing connection into a sizeable yard is acceptable. However if it was busy enough a dedicated goods line with grade separation would be a far better option, and should be do-able in 70 ft. Having the yard above or below the mains would help in this and give more visual interest. Regards Keith Link to post Share on other sites More sharing options...
Wilf Posted July 5, 2011 Author Share Posted July 5, 2011 However if it was busy enough a dedicated goods line with grade separation would be a far better option, and should be do-able in 70 ft. Having the yard above or below the mains would help in this and give more visual interest. I was considering this. The reception/departure sidings are in fact lower than the main. The sorting sidings will be accessed by a 180 degree curve over a lifting section when the time comes. I'm planning to build the main line dumb-bell first along the long wall of the barn (I don't have 50-odd tonnes of fertilizer blocking my way there), then extend the loop along the next wall (the fertilizer poses a problem for this) then finally to install the marshalling yard once I've finished the main line (by which time the fertilizer will be in the ground, unless I turn out to be some kind of lightning layout builder, which I can assure you I won't be). A grade-separated pair of tracks for access to the yard would obviously have to be built while the main was going in, not afterwards. Getting access to the far track would be difficult or impossible as it would be about 18 inches from the baseboard edge, hidden by the main line's embankment. I wouldn't be able to SEE any problem that I needed to get at, let alone reach it. I think the solution is to make the main line 2-track - this will make reaching over the main to access the rearmost track to the yard that much easier, if I'm careful I don't let it all get too far from the near edge of the board. Once the main and the yard access tracks are on the level, this can turn into 4 track main (in essence 2 concentric reversing loops) if each main line connects to its respective goods loop, thus:- Good to see you here, as well as on the MERG forums, Keith! Wilf Link to post Share on other sites More sharing options...
essexexpress Posted July 6, 2011 Share Posted July 6, 2011 But not slips Hey, I get your point, saves space etc but in modern times? (yes, should have waited to find out the OT's time period) Some of the WCML is paired by classification and some is paired by direction. Again, never really been north of Rugby, note to self "live a little!" The conflicting routes would be the same but the flexibility would be better in a ladder. Was thinking here an intermediate signal, or a nice set of G switches that could be traversed at a decent speed. Moveable angles are dependant on the crossing angle. So if we all pause and await the OPs answer we might be able to provide relevant help Totally right, I really should slow down a bit! Link to post Share on other sites More sharing options...
RMweb Gold beast66606 Posted July 6, 2011 RMweb Gold Share Posted July 6, 2011 More of a general comment, spread over lots of threads than a dig at you Essex I'm famous, amongst the old timers on here, for my invisible ink Link to post Share on other sites More sharing options...
RJS1977 Posted July 6, 2011 Share Posted July 6, 2011 You don't necessarily have to make the main line two-track. At Bishton (between Severn Tunnel Junction and Newport) the Down relief line (right hand of 4 when facing Newport) climbs over the fast lines to come out between the up relief and the fast lines (i.e. a model of this, or an equivalent dive-under would have the line in question no further back but would have the opposite line beyond it). Google maps: http://maps.google.co.uk/maps?q=Bishton,+Newport&hl=en&ll=51.579383,-2.861413&spn=0.004047,0.009645&sll=53.800651,-4.064941&sspn=15.79107,39.506836&t=h&z=17 Link to post Share on other sites More sharing options...
Wilf Posted July 6, 2011 Author Share Posted July 6, 2011 Right then, does anyone have reason to believe that my latest plan above is a load of crêpe? At the moment I've got about around 4.8m to get the trains from the marshalling yard level up to the main (that leaves extra space for gradient transitions, which unless I'm mistaken should be parabolic). I've made the reception sidings long enough to accommodate about 45 wagons if, God forbid, I should ever find myself having that much rolling stock. A little maths in my head suggests that a 1 in 72 gradient (1 inch rise per two pieces of flexitrack) will leave very little clearance under the main. Will trains of this length make it up a gradient that steep, does anyone know? I might have to play with some locos and a few wagons filled to the brim with lead... Wilf Link to post Share on other sites More sharing options...
RMweb Gold The Stationmaster Posted July 6, 2011 RMweb Gold Share Posted July 6, 2011 Right then, does anyone have reason to believe that my latest plan above is a load of crêpe? At the moment I've got about around 4.8m to get the trains from the marshalling yard level up to the main (that leaves extra space for gradient transitions, which unless I'm mistaken should be parabolic). I've made the reception sidings long enough to accommodate about 45 wagons if, God forbid, I should ever find myself having that much rolling stock. A little maths in my head suggests that a 1 in 72 gradient (1 inch rise per two pieces of flexitrack) will leave very little clearance under the main. Will trains of this length make it up a gradient that steep, does anyone know? I might have to play with some locos and a few wagons filled to the brim with lead... Wilf The NMRA in the USA has a standard for loads on grades (gradients) which they relate to curvature as well but I couldn't find it from a quick look at their website. I suspect 1 in 72 might well be too steep for many steam outline locos but ok for decent diesels with plenty of adhesion. Have a look at the NMRA site to see if you can find it and then perhaps do some tests as you suggest? Link to post Share on other sites More sharing options...
RMweb Gold The Stationmaster Posted July 6, 2011 RMweb Gold Share Posted July 6, 2011 You don't necessarily have to make the main line two-track. At Bishton (between Severn Tunnel Junction and Newport) the Down relief line (right hand of 4 when facing Newport) climbs over the fast lines to come out between the up relief and the fast lines (i.e. a model of this, or an equivalent dive-under would have the line in question no further back but would have the opposite line beyond it). Google maps: http://maps.google.c...506836&t=h&z=17 Excuse me for varying off topic but this needs correction. West of Bishton Flyover the lines are paired by use with the Main Lines on the north side and the Reliefs on the south; at Bishton Flyover the Up Relief climbs over the Main Lines to finish up on the north side of the Up Main and thus create pairing by direction between there (roughly Magor) and Severn Tunnel Jcn. This arrangement dates from 1961 when the pairing was altered to the east of Newport station to conform with the arrangement (i.e pairing by use) between Newport and Cardiff East and to allow the iron ore flow between Newport Docks and the new steelworks at Llanwern to be kept clear of the Main Lines all the way from A.D Jcn to Llanwern Works West Jcn. However it was still necessary to keep the Reliefs on the outside of the formation on the approach to Severn Tunnel Jcn yards where the Down Yard was on the Down (south) side and the Up and Bristol Yards were on the Up side - accordingly to avoid a flat crossing, and remove some of the past conflicts for traffic coming up the SWML, it was decided to construct the flyover at Bishton. Flyunder is, of course, just as good as flyover Link to post Share on other sites More sharing options...
Wilf Posted July 9, 2011 Author Share Posted July 9, 2011 Trouble with the flyover is that i do want the yard lower than the main, and it's questionable as to whether there's even space for a gradient to accommodate THAT, let alone a flyover then long gradient to take it down to below main line level. Unless I venture further out from the wall and incorporate some kind of Tehachapi type arrangement. Visually interesting, yes. Backed up by any kind of precedent in real life... no. Having had a look at how the NMRA suggest you weight your cars, I've extrapolated that the mass of the heaviest train that I could possibly try and shift from that yard will weigh... 3.82 kilograms. I can well believe that my 50 could do that easily. (What a shame it is that the more scrupulous of modellers would argue that no 50 ever operated on revenue earning freight traffic. Ah well.) I could always extend the goods lines around the loops at the end and connect them there. Link to post Share on other sites More sharing options...
essexexpress Posted July 11, 2011 Share Posted July 11, 2011 Hey Beast, no offence taken (eeeek, did I bite????), I always enjoy reading your posts. Mike More of a general comment, spread over lots of threads than a dig at you Essex I'm famous, amongst the old timers on here, for my invisible ink Link to post Share on other sites More sharing options...
Grovenor Posted July 11, 2011 Share Posted July 11, 2011 Trouble with the flyover is that i do want the yard lower than the main, and it's questionable as to whether there's even space for a gradient to accommodate THAT, let alone a flyover then long gradient to take it down to below main line level. Unless I venture further out from the wall and incorporate some kind of Tehachapi type arrangement. Visually interesting, yes. Backed up by any kind of precedent in real life... no. Yard lower than the main is how I would do it, no great shortage of real life examples, for sensible access I would put the main line on an embankment at the back and the yard in front. In this scenario the goods line could come in under the main lines. A bit like your last sketch. 70ft is more than enough for a grade seperation, don't forget the grades can be shared over both lines, ie one goes up as the other goes down. I manage a flyover in about 8ft with plenty of vertical clearance, granted my grades are steeper than you would need to use, but it does put a challenge in the operating. see Grovenor sidings. Incidentally what radius are you planning for your return loops? Regards Keith Link to post Share on other sites More sharing options...
Wilf Posted July 12, 2011 Author Share Posted July 12, 2011 I was talking about the loop when I said there were no real-world examples (not in standard-gauge britain as far as I know, at least). 70ft is more than enough for a grade seperation, don't forget the grades can be shared over both lines, ie one goes up as the other goes down. Not if I plan to have live steam running on the main line at any time - It doesn't take gradients well... Incidentally what radius are you planning for your return loops? I was going to make the radius for those a metre, which is the minimum on the whole layout. I'm fiddling around with a new idea that I had this morning - I'll get back to you if it turns out to fit. Link to post Share on other sites More sharing options...
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