Kasson S. Gibson, Geraldine Walker Haupt, and Harry J. Keegan, "Specification of Railroad Signal Colors and Glasses," J. Opt. Soc. Am. 35, 772-795 (1945)
This paper is a continuation of RP1209 and describes the cooperative work done by the Association of American Railroads Signal Section, Corning Glass Works, and the National Bureau of Standards, leading to the formulation of the AAR Signal Section specifications for signal colors and glasses. The previous paper defined the luminous transmission scale used by the signal engineers and glass manufacturers. The present paper describes the glasses selected by these engineers to define the limits of acceptable chromaticities afforded by these glasses when combined with kerosene or electric illuminant. The spectral transmissions of the glasses are given, together with the luminous transmissions and chromaticities for the specified illuminants. The photometric and colorimetric parts of the AAR Signal Section three-part specifications are illustrated, and the reasons given for the choice of tolerances both on the acceptable signal colors and on the glasses certified by the National Bureau of Standards as duplicates of the standard limit glasses. Various other data of interest are given, including the expression of the permissible chromaticities of signal colors in a uniform-chromaticity-scale coordinate system.
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No chromaticity limit is needed. The dark limit glass is useful, however, in the photometry of red signal glassware.
Non-HR green No. 87 has been accepted as the blue limit for disk greens.
These chromaticity limits have little significance. The purple glass gives a dichromatic signal, and the ratio of red to blue (or total) light is the important criterion.
Green and purple limit glasses were not selected.
In use, one side of each disk is “depolished;” no other restrictions are placed on the luminous transmissions.
Table III
Spectral transmissions, Tλ, of glasses selected by AAR Signal Section Committee VI as denning the chromaticity limits of railroad signal colors.
Wavelength in millimicrons
Red
Yellow
Green
Blue
Purple
Lunar white
Pressed ware and disk
Highway crossing
Hand lantern globes
Pressed ware
Disk
Hand lantern globes
Pressed ware
Disk
Hand lantern globes
Pressed ware
Hand lantern globes
Kerosene
Electric
Kerosene
Electric
L
D
L
D
L
D
L
D
—
—
L
D
L
D
L
D
L
D
L
D
L
D
L
D
L
D
L
D
L
D
154
86
75
400
201
211
141
142
199
200
261
271
134
87
139
140
137
322
47
57
141
131
56
47
80
108
45
74
124
73
380
0.008
0.0002
0.0008
0.121
0.073
0.097
0.040
0.230
0.13
0.579
0.442
0.50
0.45
0.835
0.783
0.886
0.875
0.828
0.835
0.825
0.819
90
.008
.0002
.0009
.242
.152
.150
.082
.294
.19
.716
.596
.63
.58
.853
.849
.867
.858
.856
.854
.875
.890
400
.0075
.0002
.0010
.335
.237
.207
.126
.356
.247
.770
.675
.710
.655
.857
.852
.838
.827
.873
.867
.888
.900
10
.0074
.0002
.0014
.405
.307
.266
.174
.408
.304
.790
.718
.738
.685
.831
.823
.787
.780
.867
.858
.884
.888
20
.0076
.0003
.0020
.465
.366
.315
.222
.457
.362
.785
.731
.742
.691
.798
.779
.727
.714
.847
.830
.876
.869
30
.0087
.0004
.0028
.521
.425
.371
.273
.505
.416
.771
.726
.734
.680
.763
.733
.647
.625
.838
.820
.871
.860
40
.0113
.0007
.0039
.565
.480
.414
.326
.545
.465
.751
.707
.717
.659
.727
.684
.558
.527
.830
.807
.866
.851
450
.0169
.0014
.0054
.617
.541
.459
.373
.582
.512
.719
.673
.693
.630
.676
.625
.448
.422
.818
.792
.862
.842
60
.0271
.0030
.0075
.659
.588
.503
.423
.620
.552
.670
.625
.652
.576
.615
.552
.328
.302
.800
.769
.851
.826
70
.0423
.0064
.0101
.686
.625
.540
.459
.645
.581
.590
.530
.564
.470
.504
.426
.197
.172
.764
.718
.824
.792
80
.0636
.0126
.0137
.696
.638
.565
.483
.662
.600
.467
.393
.426
.320
.355
.269
.098
.077
.698
.637
.783
.733
90
.0952
.0238
.0190
.695
.633
.577
.501
.666
.600
.331
.258
.286
.186
.214
.1397
.0408
.0304
.612
.535
.732
.656
500.
.1324
.0424
0.0000
.0289
0.000
.680
.618
.578
.501
.658
.580
.225
.165
.197
.112
.1305
.0713
.0189
.0130
.542
.446
.672
.583
10
.186
.0712
.0001
.0526
.001
.656
.584
.569
.483
.628
.540
.1362
.0854
.117
.0529
.0636
.0275
.0076
.0045
.450
.350
.598
.495
20
.241
.1102
.0003
.0826
.120
0.000
.610
.526
.536
.450
.578
.481
.0710
.0376
.0601
.0215
.0266
.0087
.0032
.0017
.357
.258
.520
.408
30
.303
.158
.0126
.1125
.518
.001
.540
.450
.493
.396
.509
.404
.0319
.0135
.0270
.0075
.0088
.0022
.0016
.0007
.266
.174
.434
.319
40
.367
.214
.289
.157
.705
.048
.462
.366
.430
.333
.434
.319
.0191
.0072
.0188
.0044
.0050
.0010
.0017
.0008
.230
.143
.397
.281
550
.430
.277
.654
.277
.767
.433
.382
.279
.358
.266
.347
.234
.0219
.0084
.0244
.0067
.0073
.0017
.0039
.0019
.255
.164
.423
.307
60
.492
.339
.784
.544
.796
.670
.301
.205
.292
.201
.265
.164
.0325
.0123
.0361
.0109
.0147
.0042
.0056
.0029
.306
.211
.470
.357
70
0.0000
.542
.399
.826
.770
.818
.738
.230
.1424
.224
.1442
.196
.105
.0254
.0083
.0280
.0071
.0119
.0031
.0023
.0011
.291
.195
.462
.342
80
.0001
0.0000
0.000
.589
.451
.844
.848
.835
.774
.171
.0952
.172
.0996
.1390
.064
.0092
.0022
.0096
.0016
.0033
.0006
.0004
.0002
.203
.1231
.373
.253
90
0.0000
.0002
.037
0.0000
.001
.625
.495
.857
.873
.848
.803
.1211
.0609
.1240
.0660
.0968
.0372
.0024
.0004
.0026
.0003
.0006
.0001
.0001
.0000
.l32
.0675
.282
.173
600
.0003
.0005
.27
.010
.051
0.000
.654
.532
.864
.882
.859
.824
.0856
.0375
.0902
.0428
.0653
.0217
.0020
.0003
.0021
.0002
.0005
.0001
.0001
.0000
.128
.0651
.277
.170
10
.037
.0019
.54
.16
.41
.004
.676
.559
.869
.887
.866
.840
.0588
.0225
.0642
.0276
.0437
.0124
.0022
.0003
.0021
.0002
.0007
.0001
.0001
.0001
.141
.0743
.293
.185
20
.41
.022
.685
.60
.715
.22
.693
.579
.874
.890
.870
.854
.0402
.0134
.0460
.0173
.0289
.0072
.0019
.0002
.0023
.0003
.0008
.0001
.0001
.0001
.145
.0778
.299
.190
30
.71
.23
.742
.796
.805
.60
.705
.593
.879
.892
.873
.863
.0270
.0084
.0322
.0109
.0190
.0041
.0015
.0002
.0021
.0002
.0007
.0001
.0001
.0001
.138
.0740
.292
.183
40
.796
.65
.771
.848
.835
.734
.713
.599
.883
.893
.875
.871
.0182
.0051
.0230
.0070
.0127
.0024
.0010
.0001
.0016
.0001
.0005
.0001
.0001
.0000
.128
.0654
.276
.168
650
.820
.798
.790
.866
.846
.784
.718
.602
.887
.894
.876
.877
.0124
.0031
.0167
.0046
.0088
.0015
.0010
.0001
.0015
.0001
.0006
.0001
.0001
.0000
.131
.0688
.283
.174
60
.833
.833
.804
.873
.853
.803
.721
.603
.889
.894
.877
.880
.0088
.0019
.0122
.0031
.0062
.001
.0015
.0002
.0020
.0002
.0018
.0003
.0002
.0001
.165
.0942
.327
.214
70
.842
.844
.817
.879
.858
.813
.723
.601
.890
.894
.877
.883
.006
.001
.0093
.0021
.0045
.000
.0035
.0003
.0054
.0006
.0075
.0015
.0012
.0004
.248
.161
.425
.302
80
.848
852
.826
.881
.860
.820
.723
.596
.891
.894
.876
.884
.004
.000
.0070
.0014
.003
.0109
.0005
.017
.0032
.043
.016
.0080
.0045
.398
.303
.560
.453
90
.851
.856
.834
.882
.861
.825
.722
.588
.891
.893
.875
.885
.003
.0054
.001
.0025
.0275
.0020
.042
.014
.19
.11
.045
.036
.587
.514
.707
.628
700
.853
.858
.841
.883
.862
.826
.720
.580
.891
.892
.873
.884
.002
.0042
.000
.002
.042
.0030
.071
.027
.44
.35
.18
.16
.734
.700
.810
.766
10
.852
.859
.846
.884
.860
.826
.717
.570
.891
.890
.871
.882
.0015
.0033
.0015
.050
.0040
.090
.037
.68
.61
.41
.38
.821
.812
.865
.846
20
.850
.858
.851
.883
.857
.824
.712
.560
.890
.888
.868
.880
.001
.0026
.001
.051
.0041
.096
.041
.80
.77
.62
.60
.854
.862
.888
.880
30
.848
.857
.854
.881
.855
.821
.706
.548
.889
.886
.865
.879
.000
.0021
.000
.049
.0037
.096
.040
.859
.84
.76
.75
.872
.884
.900
.892
40
.846
.855
.857
.879
.852
.818
.700
.535
.888
.884
.862
.877
.0017
.047
.0034
.093
.039
.882
.874
.84
.83
.877
.893
.902
.897
750
.843
.852
.857
.877
.848
.814
.692
.522
.886
.883
.859
.875
.0014
.045
.0031
.090
.037
.892
.885
.878
.875
.878
.895
.903
.899
60
.840
.849
.857
.875
.844
.809
.683
.507
.884
.882
.856
.873
.0011
.043
.0026
.087
.035
.895
.889
.897
.895
.878
.895
.904
.900
70
.836
.846
.857
.873
.841
.805
.673
.492
.882
.881
.853
.871
.0008
.041
.0021
.084
.033
.896
.890
.902
.902
.878
.895
.904
.900
TAAR =
177.0
102.9
288.2
217.6
256.7
145.5
214.1
160.8
270.5
251.0
297.4
241.2
205.9
150.5
193.4
138.7
184.9
126.6
130.2
74.7
124.8
56.0
131.2
73.3
40.1
30.3
121.7
79.6
205.3
146.6
Table IV
Luminous transmissions, Tw, ratios of red to total luminous transmission, Tr/Tw, and chromaticity coordinates, x, y, z, for glasses selected by AAR Signal Section Committee VI as defining the chromaticity limits of railroad signal colors.
Color designation
Number of glass
Illuminant at 1900 °K
Illuminant at 2360 °K
Illuminant at 2848 °K
x
y
z
Tw
x
y
z
Tw
TAAR
Tr/Tw
x
y
z
Tw
Red
154
0.7148
0.2852
0.0000
0.1564
0.7138
0.2862
0.0000
0.1222
177.0
—
0.7132
0.2867
0.0000
0.1009
86
.7234
.2766
.0000
.0944
.7228
.2772
.0000
.0711
102.9
—
.7224
.2776
.0000
.0572
75
.6967
.3032
.0001
.2431
.6944
.3055
.0001
.1989
288.2
—
.6927
.3072
.0001
.1698
400
.7108
.2891
.0001
.1898
.7096
.2904
.0001
.1502
217.6
—
.7088
.2912
.0001
.1251
201
.7051
.2948
.0001
.2205
.7036
.2963
.0001
.1771
256.7
—
.7025
.2974
.0001
.1493
211
.7178
.2822
.0000
.1300
.7171
.2829
.0000
.1004
145.5
—
.7165
.2835
.0000
.0823
Yellow
141
.5963
.3976
.0062
.5571
.5740
.4157
.0103
.5296
214.1
—
.5560
.4291
.0149
.5082
142
.6113
.3861
.0027
.4262
.5934
.4026
.0041
.3978
160.8
—
.5794
.4151
.0056
.3762
199
.6036
.3955
.0009
.7137
.5878
.4111
.0011
.6692
270.5
—
.5762
.4226
.0012
.6334
200
.6147
.3836
.0018
.6708
.6000
.3972
.0027
.6210
251.0
—
.5889
.4073
.0038
.5823
261
.5873
.4107
.0020
.7669
.5669
.4306
.0026
.7358
297.4
—
.5515
.4454
.0030
.7095
271
.6151
.3843
.0007
.6456
.6014
.3979
.0008
.5967
241.2
—
.5913
.4078
.0009
.5584
Green
134
.3197
.4944
.1859
.2106
.2749
.4550
.2702
.2442
205.9
—
.2448
.4145
.3407
.2698
87
.2684
.4976
.2340
.1492
.2316
.4472
.3212
.1784
150.5
—
.2084
.4016
.3899
.2013
139
.3407
.5025
.1568
.2002
.2951
.4721
.2328
.2294
193.4
—
.2634
.4376
.2990
.2515
140
.2949
.5138
.1913
.1397
.2555
.4742
.2702
.1645
138.7
—
.2295
.4348
.3357
.1835
137
.3025
.4974
.2001
.1872
.2602
.4542
.2856
.2193
184.9
—
.2324
.4116
.3561
.2440
322
.2415
.4942
.2643
.1236
.2099
.4376
.3525
.1502
126.6
—
.1909
.3891
.4200
.1712
Blue
47
.1783
.2049
.6168
.02216
.1595
.1521
.6884
.02909
130.2
0.0089
.1530
.1221
.7249
.03556
57
.1458
.1387
.7154
.01164
.1436
.1051
.7514
.01669
74.7
.0011
.1440
.0862
.7698
.02155
141
.1916
.2070
.6014
.02173
.1665
.1522
.6812
.02789
124.8
.0147
.1575
.1212
.7213
.03372
131
.1543
.1187
.7270
.00876
.1482
.0889
.7630
.01252
56.0
.0088
.1474
.0728
.7798
.01626
Purple
56
.2280
.1475
.6245
.01386
.1765
.1035
.7200
.01692
131.2
.116
.1610
.0818
.7572
.02062
47
.2158
.1000
.6842
.00752
.1700
.0690
.7610
.00945
73.3
.158
.1579
.0552
.7869
.01200
80
.2292
.0904
.6804
.00443
.1799
.0564
.7636
.00517
40.1
.188
.1661
.0426
.7913
.00634
108
.2277
.0758
.6965
.00336
.1786
.0463
.7750
.00390
30.3
.227
.1658
.0352
.7990
.00485
Lunar white
45
.4395
.3981
.1624
.2173
.3651
.3664
.2685
.2306
121.7
—
.3122
.3279
.3599
.2421
74
.4005
.3766
.2229
.1394
.3216
.3308
.3476
.1509
79.6
—
.2711
.2852
.4437
.1612
124
.4822
.4106
.1072
.3755
.4169
.3953
.1878
.3891
205.3
—
.3654
.3688
.2658
.4004
73
.4556
.4032
.1413
.2643
.3840
.3772
.2388
.2779
146.6
—
.3308
.3426
.3266
.2895
Table V
Maximum chromaticity deviations permitted for glasses certified as duplicates of standard limit glasses for railroad signaling, AAR Signal Section Specifications 69-40 and 59-39.
Color designation
Number of glass
Color temperature of illuminant °K
Chromaticity coordinates, x, y, z, and maximum deviations, Δx, Δy, Δz, for glasses and illuminants indicated
This tolerance is given in Part A of the signal glass specifications. In effect it limits the tolerances of ±0.0008 in x and y for the dark limit glasses, as shown in Fig. 10.
Table VI
Maximum deviations of luminous transmission on the AAR scale, TAAR, and of red to total luminous transmission, Tr/Tw, both for 2360°K, permitted for glasses certified as duplicates of standard limit glasses for railroad signaling, AAR Signal Section Specifications 69-40 and 59-39.
No chromaticity limit is needed. The dark limit glass is useful, however, in the photometry of red signal glassware.
Non-HR green No. 87 has been accepted as the blue limit for disk greens.
These chromaticity limits have little significance. The purple glass gives a dichromatic signal, and the ratio of red to blue (or total) light is the important criterion.
Green and purple limit glasses were not selected.
In use, one side of each disk is “depolished;” no other restrictions are placed on the luminous transmissions.
Table III
Spectral transmissions, Tλ, of glasses selected by AAR Signal Section Committee VI as denning the chromaticity limits of railroad signal colors.
Wavelength in millimicrons
Red
Yellow
Green
Blue
Purple
Lunar white
Pressed ware and disk
Highway crossing
Hand lantern globes
Pressed ware
Disk
Hand lantern globes
Pressed ware
Disk
Hand lantern globes
Pressed ware
Hand lantern globes
Kerosene
Electric
Kerosene
Electric
L
D
L
D
L
D
L
D
—
—
L
D
L
D
L
D
L
D
L
D
L
D
L
D
L
D
L
D
L
D
154
86
75
400
201
211
141
142
199
200
261
271
134
87
139
140
137
322
47
57
141
131
56
47
80
108
45
74
124
73
380
0.008
0.0002
0.0008
0.121
0.073
0.097
0.040
0.230
0.13
0.579
0.442
0.50
0.45
0.835
0.783
0.886
0.875
0.828
0.835
0.825
0.819
90
.008
.0002
.0009
.242
.152
.150
.082
.294
.19
.716
.596
.63
.58
.853
.849
.867
.858
.856
.854
.875
.890
400
.0075
.0002
.0010
.335
.237
.207
.126
.356
.247
.770
.675
.710
.655
.857
.852
.838
.827
.873
.867
.888
.900
10
.0074
.0002
.0014
.405
.307
.266
.174
.408
.304
.790
.718
.738
.685
.831
.823
.787
.780
.867
.858
.884
.888
20
.0076
.0003
.0020
.465
.366
.315
.222
.457
.362
.785
.731
.742
.691
.798
.779
.727
.714
.847
.830
.876
.869
30
.0087
.0004
.0028
.521
.425
.371
.273
.505
.416
.771
.726
.734
.680
.763
.733
.647
.625
.838
.820
.871
.860
40
.0113
.0007
.0039
.565
.480
.414
.326
.545
.465
.751
.707
.717
.659
.727
.684
.558
.527
.830
.807
.866
.851
450
.0169
.0014
.0054
.617
.541
.459
.373
.582
.512
.719
.673
.693
.630
.676
.625
.448
.422
.818
.792
.862
.842
60
.0271
.0030
.0075
.659
.588
.503
.423
.620
.552
.670
.625
.652
.576
.615
.552
.328
.302
.800
.769
.851
.826
70
.0423
.0064
.0101
.686
.625
.540
.459
.645
.581
.590
.530
.564
.470
.504
.426
.197
.172
.764
.718
.824
.792
80
.0636
.0126
.0137
.696
.638
.565
.483
.662
.600
.467
.393
.426
.320
.355
.269
.098
.077
.698
.637
.783
.733
90
.0952
.0238
.0190
.695
.633
.577
.501
.666
.600
.331
.258
.286
.186
.214
.1397
.0408
.0304
.612
.535
.732
.656
500.
.1324
.0424
0.0000
.0289
0.000
.680
.618
.578
.501
.658
.580
.225
.165
.197
.112
.1305
.0713
.0189
.0130
.542
.446
.672
.583
10
.186
.0712
.0001
.0526
.001
.656
.584
.569
.483
.628
.540
.1362
.0854
.117
.0529
.0636
.0275
.0076
.0045
.450
.350
.598
.495
20
.241
.1102
.0003
.0826
.120
0.000
.610
.526
.536
.450
.578
.481
.0710
.0376
.0601
.0215
.0266
.0087
.0032
.0017
.357
.258
.520
.408
30
.303
.158
.0126
.1125
.518
.001
.540
.450
.493
.396
.509
.404
.0319
.0135
.0270
.0075
.0088
.0022
.0016
.0007
.266
.174
.434
.319
40
.367
.214
.289
.157
.705
.048
.462
.366
.430
.333
.434
.319
.0191
.0072
.0188
.0044
.0050
.0010
.0017
.0008
.230
.143
.397
.281
550
.430
.277
.654
.277
.767
.433
.382
.279
.358
.266
.347
.234
.0219
.0084
.0244
.0067
.0073
.0017
.0039
.0019
.255
.164
.423
.307
60
.492
.339
.784
.544
.796
.670
.301
.205
.292
.201
.265
.164
.0325
.0123
.0361
.0109
.0147
.0042
.0056
.0029
.306
.211
.470
.357
70
0.0000
.542
.399
.826
.770
.818
.738
.230
.1424
.224
.1442
.196
.105
.0254
.0083
.0280
.0071
.0119
.0031
.0023
.0011
.291
.195
.462
.342
80
.0001
0.0000
0.000
.589
.451
.844
.848
.835
.774
.171
.0952
.172
.0996
.1390
.064
.0092
.0022
.0096
.0016
.0033
.0006
.0004
.0002
.203
.1231
.373
.253
90
0.0000
.0002
.037
0.0000
.001
.625
.495
.857
.873
.848
.803
.1211
.0609
.1240
.0660
.0968
.0372
.0024
.0004
.0026
.0003
.0006
.0001
.0001
.0000
.l32
.0675
.282
.173
600
.0003
.0005
.27
.010
.051
0.000
.654
.532
.864
.882
.859
.824
.0856
.0375
.0902
.0428
.0653
.0217
.0020
.0003
.0021
.0002
.0005
.0001
.0001
.0000
.128
.0651
.277
.170
10
.037
.0019
.54
.16
.41
.004
.676
.559
.869
.887
.866
.840
.0588
.0225
.0642
.0276
.0437
.0124
.0022
.0003
.0021
.0002
.0007
.0001
.0001
.0001
.141
.0743
.293
.185
20
.41
.022
.685
.60
.715
.22
.693
.579
.874
.890
.870
.854
.0402
.0134
.0460
.0173
.0289
.0072
.0019
.0002
.0023
.0003
.0008
.0001
.0001
.0001
.145
.0778
.299
.190
30
.71
.23
.742
.796
.805
.60
.705
.593
.879
.892
.873
.863
.0270
.0084
.0322
.0109
.0190
.0041
.0015
.0002
.0021
.0002
.0007
.0001
.0001
.0001
.138
.0740
.292
.183
40
.796
.65
.771
.848
.835
.734
.713
.599
.883
.893
.875
.871
.0182
.0051
.0230
.0070
.0127
.0024
.0010
.0001
.0016
.0001
.0005
.0001
.0001
.0000
.128
.0654
.276
.168
650
.820
.798
.790
.866
.846
.784
.718
.602
.887
.894
.876
.877
.0124
.0031
.0167
.0046
.0088
.0015
.0010
.0001
.0015
.0001
.0006
.0001
.0001
.0000
.131
.0688
.283
.174
60
.833
.833
.804
.873
.853
.803
.721
.603
.889
.894
.877
.880
.0088
.0019
.0122
.0031
.0062
.001
.0015
.0002
.0020
.0002
.0018
.0003
.0002
.0001
.165
.0942
.327
.214
70
.842
.844
.817
.879
.858
.813
.723
.601
.890
.894
.877
.883
.006
.001
.0093
.0021
.0045
.000
.0035
.0003
.0054
.0006
.0075
.0015
.0012
.0004
.248
.161
.425
.302
80
.848
852
.826
.881
.860
.820
.723
.596
.891
.894
.876
.884
.004
.000
.0070
.0014
.003
.0109
.0005
.017
.0032
.043
.016
.0080
.0045
.398
.303
.560
.453
90
.851
.856
.834
.882
.861
.825
.722
.588
.891
.893
.875
.885
.003
.0054
.001
.0025
.0275
.0020
.042
.014
.19
.11
.045
.036
.587
.514
.707
.628
700
.853
.858
.841
.883
.862
.826
.720
.580
.891
.892
.873
.884
.002
.0042
.000
.002
.042
.0030
.071
.027
.44
.35
.18
.16
.734
.700
.810
.766
10
.852
.859
.846
.884
.860
.826
.717
.570
.891
.890
.871
.882
.0015
.0033
.0015
.050
.0040
.090
.037
.68
.61
.41
.38
.821
.812
.865
.846
20
.850
.858
.851
.883
.857
.824
.712
.560
.890
.888
.868
.880
.001
.0026
.001
.051
.0041
.096
.041
.80
.77
.62
.60
.854
.862
.888
.880
30
.848
.857
.854
.881
.855
.821
.706
.548
.889
.886
.865
.879
.000
.0021
.000
.049
.0037
.096
.040
.859
.84
.76
.75
.872
.884
.900
.892
40
.846
.855
.857
.879
.852
.818
.700
.535
.888
.884
.862
.877
.0017
.047
.0034
.093
.039
.882
.874
.84
.83
.877
.893
.902
.897
750
.843
.852
.857
.877
.848
.814
.692
.522
.886
.883
.859
.875
.0014
.045
.0031
.090
.037
.892
.885
.878
.875
.878
.895
.903
.899
60
.840
.849
.857
.875
.844
.809
.683
.507
.884
.882
.856
.873
.0011
.043
.0026
.087
.035
.895
.889
.897
.895
.878
.895
.904
.900
70
.836
.846
.857
.873
.841
.805
.673
.492
.882
.881
.853
.871
.0008
.041
.0021
.084
.033
.896
.890
.902
.902
.878
.895
.904
.900
TAAR =
177.0
102.9
288.2
217.6
256.7
145.5
214.1
160.8
270.5
251.0
297.4
241.2
205.9
150.5
193.4
138.7
184.9
126.6
130.2
74.7
124.8
56.0
131.2
73.3
40.1
30.3
121.7
79.6
205.3
146.6
Table IV
Luminous transmissions, Tw, ratios of red to total luminous transmission, Tr/Tw, and chromaticity coordinates, x, y, z, for glasses selected by AAR Signal Section Committee VI as defining the chromaticity limits of railroad signal colors.
Color designation
Number of glass
Illuminant at 1900 °K
Illuminant at 2360 °K
Illuminant at 2848 °K
x
y
z
Tw
x
y
z
Tw
TAAR
Tr/Tw
x
y
z
Tw
Red
154
0.7148
0.2852
0.0000
0.1564
0.7138
0.2862
0.0000
0.1222
177.0
—
0.7132
0.2867
0.0000
0.1009
86
.7234
.2766
.0000
.0944
.7228
.2772
.0000
.0711
102.9
—
.7224
.2776
.0000
.0572
75
.6967
.3032
.0001
.2431
.6944
.3055
.0001
.1989
288.2
—
.6927
.3072
.0001
.1698
400
.7108
.2891
.0001
.1898
.7096
.2904
.0001
.1502
217.6
—
.7088
.2912
.0001
.1251
201
.7051
.2948
.0001
.2205
.7036
.2963
.0001
.1771
256.7
—
.7025
.2974
.0001
.1493
211
.7178
.2822
.0000
.1300
.7171
.2829
.0000
.1004
145.5
—
.7165
.2835
.0000
.0823
Yellow
141
.5963
.3976
.0062
.5571
.5740
.4157
.0103
.5296
214.1
—
.5560
.4291
.0149
.5082
142
.6113
.3861
.0027
.4262
.5934
.4026
.0041
.3978
160.8
—
.5794
.4151
.0056
.3762
199
.6036
.3955
.0009
.7137
.5878
.4111
.0011
.6692
270.5
—
.5762
.4226
.0012
.6334
200
.6147
.3836
.0018
.6708
.6000
.3972
.0027
.6210
251.0
—
.5889
.4073
.0038
.5823
261
.5873
.4107
.0020
.7669
.5669
.4306
.0026
.7358
297.4
—
.5515
.4454
.0030
.7095
271
.6151
.3843
.0007
.6456
.6014
.3979
.0008
.5967
241.2
—
.5913
.4078
.0009
.5584
Green
134
.3197
.4944
.1859
.2106
.2749
.4550
.2702
.2442
205.9
—
.2448
.4145
.3407
.2698
87
.2684
.4976
.2340
.1492
.2316
.4472
.3212
.1784
150.5
—
.2084
.4016
.3899
.2013
139
.3407
.5025
.1568
.2002
.2951
.4721
.2328
.2294
193.4
—
.2634
.4376
.2990
.2515
140
.2949
.5138
.1913
.1397
.2555
.4742
.2702
.1645
138.7
—
.2295
.4348
.3357
.1835
137
.3025
.4974
.2001
.1872
.2602
.4542
.2856
.2193
184.9
—
.2324
.4116
.3561
.2440
322
.2415
.4942
.2643
.1236
.2099
.4376
.3525
.1502
126.6
—
.1909
.3891
.4200
.1712
Blue
47
.1783
.2049
.6168
.02216
.1595
.1521
.6884
.02909
130.2
0.0089
.1530
.1221
.7249
.03556
57
.1458
.1387
.7154
.01164
.1436
.1051
.7514
.01669
74.7
.0011
.1440
.0862
.7698
.02155
141
.1916
.2070
.6014
.02173
.1665
.1522
.6812
.02789
124.8
.0147
.1575
.1212
.7213
.03372
131
.1543
.1187
.7270
.00876
.1482
.0889
.7630
.01252
56.0
.0088
.1474
.0728
.7798
.01626
Purple
56
.2280
.1475
.6245
.01386
.1765
.1035
.7200
.01692
131.2
.116
.1610
.0818
.7572
.02062
47
.2158
.1000
.6842
.00752
.1700
.0690
.7610
.00945
73.3
.158
.1579
.0552
.7869
.01200
80
.2292
.0904
.6804
.00443
.1799
.0564
.7636
.00517
40.1
.188
.1661
.0426
.7913
.00634
108
.2277
.0758
.6965
.00336
.1786
.0463
.7750
.00390
30.3
.227
.1658
.0352
.7990
.00485
Lunar white
45
.4395
.3981
.1624
.2173
.3651
.3664
.2685
.2306
121.7
—
.3122
.3279
.3599
.2421
74
.4005
.3766
.2229
.1394
.3216
.3308
.3476
.1509
79.6
—
.2711
.2852
.4437
.1612
124
.4822
.4106
.1072
.3755
.4169
.3953
.1878
.3891
205.3
—
.3654
.3688
.2658
.4004
73
.4556
.4032
.1413
.2643
.3840
.3772
.2388
.2779
146.6
—
.3308
.3426
.3266
.2895
Table V
Maximum chromaticity deviations permitted for glasses certified as duplicates of standard limit glasses for railroad signaling, AAR Signal Section Specifications 69-40 and 59-39.
Color designation
Number of glass
Color temperature of illuminant °K
Chromaticity coordinates, x, y, z, and maximum deviations, Δx, Δy, Δz, for glasses and illuminants indicated
This tolerance is given in Part A of the signal glass specifications. In effect it limits the tolerances of ±0.0008 in x and y for the dark limit glasses, as shown in Fig. 10.
Table VI
Maximum deviations of luminous transmission on the AAR scale, TAAR, and of red to total luminous transmission, Tr/Tw, both for 2360°K, permitted for glasses certified as duplicates of standard limit glasses for railroad signaling, AAR Signal Section Specifications 69-40 and 59-39.