Short lengths for inner / low rail on curves

[HGR]

A question for P-Way practitioners, if you would please :

From what I remember, PADS (or CatMaster as was) used to have catalogue numbers for 60 foot rails either undrilled, or drilled (broached / cold-formed) with fishplate holes. For the inside rails of curves, where an under-length rail has to be used every so-many panels to keep the rail joints level, I think there were 1", 2", and 4" under-lengths (i.e. 59' 11", 59' 10", and 59' 8"). These were available as 95RBH bullhead, or 113A flat bottomed, presumably only as pre-drilled for jointed track.

My question is, were these a more 'modern' offering, and before that were there only short rails that were 4-1/2" shorter than nominal length, at 59' 7-1/2" ?

This would be equivalent to one hole pitch of the fishplates. Were these rails available 'shop made', or were they produced on-site by cutting off 4-1/2" from one end of a full length rail and then drilling and broaching an extra hole inboard of the remaining original hole at that end ?

 

A further variation on the theme would appear to be 2-1/4" under-length, such as 59' 9-3/4" which would if a pre-drilled 60' imply chopping off at the first hole, then re-drilling in between the two original holes, and a further half-pitch inboard. That would be evident in then having three closely spaced holes at the cut end.

 

[Trog]

When I was surveying for prefab relaying in the 1980's you measured the lead of the inside rail every 60'-0" with a T square and tape measure the panels were then built up with the rails ends that far out of square. (If you do that when the panels are curved to the desired alignment on site the rail ends will be the same distance apart.) Until the lead  of the inside rail reached half the fish plate bolt spacing for the rail section you were using.

 

You then specified a short rail to go into the inside rail which was short by the bolt spacing so that the out side rail would then lead by half the bolt spacing instead, as you carried on round the curve the outside rails lead would reduce until the inside rail again took the lead, when the inside rails lead again reached half the bolt hole spacing you would specify another short rail. There is a British Transport film that shows the surveying process quite well, although the relaying its self is done to some rather strange WR method.

 

Tip when marking rails use a light red or green crayon, as it shows up much better than a pencil.

[Trog]

3 hours ago, HGR said:

A further variation on the theme would appear to be 2-1/4" under-length, such as 59' 9-3/4" which would if a pre-drilled 60' imply chopping off at the first hole, then re-drilling in between the two original holes, and a further half-pitch inboard. That would be evident in then having three closely spaced holes at the cut end.

 

 

Would this be a way of getting rid of rail end batter on serviceable rails? I think there was such a thing as three hole fish plates possibly an LNER idea which could have been used with such rails, certainly it would have avoided having so many holes so close together.

[HGR]

Not sure of regional variations, but the technique I was aware of in re-using panels or rails that had battered ends was to cut off one foot of length, so you in effect ended up with 58' panels with good ends.

 

The Southern Railway had three-hole fishplates where the centre bolt had a 'half hole' in each rail end. Easy enough to notch a rail end in the shop but not sure how easy that could be done out on site.

 

I think I've seen the BTC film showing a track survey being done. A notebook with pre-ruled column lines for the rail lengths either side and joint lead triggers vague distant memories.

 

Also worth remembering that the length of new rails is the nominal plus or minus 3/16" (+/-5mm). This seems to be better with rails from about the 1960s or later, but can be more like up to 1/2" over length with old 30' panels. Add to that the expansion gaps which sometimes seemed to be far more generous than expected for the temperature, but on one side only - and not because of rail creep either ! Don't think the bag of metal legs ('L' shaped spacers) came in to it when gapping the rails.

 

[NorthEndCab]

22 hours ago, HGR said:

I think I've seen the BTC film showing a track survey being done. A notebook with pre-ruled column lines for the rail lengths either side and joint lead triggers vague distant memories.

 

 

This one?