document some peco part numbers

[trains.git] / layout / parts.i4

diff --git a/layout/parts.i4 b/layout/parts.i4
index f89acb38fce89c69da7f5bfff5a6ec83adab9b39..6f36f355706820666aa29c8abbc39c4f4ba9ce21 100644 (file)
--- a/layout/parts.i4
+++ b/layout/parts.i4
@@ -6,6 +6,12 @@ dnl OBJNAME-EXCLUDING-L
  enddef
 ')
 
+# Conventionally, points' toes are c, the straight through is a
+# and the curve is b.  Segments run from c towards a and b.
+#
+# Crossings (including slips) run `vertically' and have
+# tl, tr, bl, br.  Segments run from b* to t*.
+
 define(`def_point_ord',`
 dnl OBJNAME-EXCLUDING-PT-L ANGLE STRAIGHT-L CURVE-LONGER CURVE-DIVERGE-Y MIN-R
  defpart pt_$1l
@@ -61,10 +67,11 @@ dnl OBJNAME-EXCLUDING-CROSS HALF-ANG HALF-LENGTH
  enddef
 ')
 
-def_point_ord(`peco_s', 22.5, 87,  -0.5, 17,    200) # not minr 230 ?
-def_point_ord(`peco_m', 14,  126.5,-1.55,13.21, 315) # not minr 457 ?
-def_point_ord(`peco_l',  8,  160,  -0.4, 13.21, 914)
+def_point_ord(`peco_s', 22.5, 87,  -0.5, 17,    200) #ST-5,6     not minr 230 ?
+def_point_ord(`peco_m', 14,  126.5,-1.55,13.21, 315) #SL-395,396 not minr 457 ?
+def_point_ord(`peco_l',  8,  160,  -0.4, 13.21, 914) #SL-388,389
  # catalogue says 123.7 for STRAIGHT-L ?!
+ # SL-<n> and SL-E<n> have the same geometry
 
 def_point_curve(`peco_c',  10, 154.4, 13.8,  3, 156.0, 0.8, 457)
  dnl 163.2-  } dist to markings on paper cribsheet from c
@@ -138,9 +145,11 @@ dnl OBJNAME-EXCLUDING-SLIP2 HALF-LEN HALF-ANG
   rel m mr 0 0 -$3
   segment /S2
   extend ml tl len $2
+  segment -/S2
   extend ml br len -$2
   segment /S1
   extend mr tr len $2
+  segment -/S1
   extend mr bl len -$2
   segment /S0
   join bl tl 500
@@ -242,7 +251,7 @@ defpart tt_atlas_motor
  layer p
  rel cout bl -40 -40
  rel cout br -40  40
- extend bl tl len 100
- extend br tr len 100
+ extend bl tl len 89
+ extend br tr len 89
  join tl -tr 0.1
 enddef