770:
investment limited to what the market would come up with, building a line as cheaply and quickly as possible was crucial to giving a good return on investment. With resources limited to horse-drawn implements, humans with hand tools and the occasional explosives, the over-riding task was to minimise earthworks. Given that locomotives of the time were limited in power and that steep gradients were anathema to slow-speed trains, that meant going around contour lines. This gave two advantages for narrow gauge: first, as mentioned, smaller dimensions, hence lighter weight, of rolling stock required smaller earthworks (the saving through the gauge being, say, 1 foot to 1'-6" narrower was relatively minor in this); second, because their wheelbases were shorter, narrow-gauge steam locomotives were able to negotiate the tighter curves mandated by the need to "crawl around the contours" — and in fact even then, narrow gauge loco wheelbases were a limiting factor until articulated locos were developed (see
854:
area in which it was built. Often, a narrow gauge was chosen to keep within a very small budget when a line was initiated to develop economically promising resources, whether agricultural or mineralogical. Narrower gauge railways cost less to build, for several reasons. First, the dimensions of locomotives and rolling stock were smaller in order to limit train weight on track and bridges and to limit the amount of rock to be removed in tunnels. Second, to maximise the tonnage that could be hauled by low-powered steam locomotives of the time, track had to be built as level as possible. That necessitated trains going around contour lines if earthworks were to be kept to a minimum, which was necessary when horse-drawn implements, humans with hand tools, and occasional explosives were the only available resources. Third, because narrow-gauge steam locomotives were smaller than those of the larger gauges, their
32:
492:
372:
1031:, who led Australia's first but unsuccessful (like all the others) high-speed rail project, used to write exam qustions for physics students in their final year before going to university, and I remmebr one to that effect. In practice, passenger comfort (or rather the lack of it) takes place well before there is any such prospect. That's why a minimum horizontal radius of 7 km / 4 mi was specified for 350 km/h trains.
334:
544:
574:
358:
817:
terrain isn't all that hilly, as you'll see if you go to Street View. The size of the earthworks needed to attain that almost straight route can be seen if you "drive" north-east for a few hundred yards and look to the right, where you'll see a long embankment. Constructing that single embankment required vastly more earth to be moved than in the entire section of the narrow gauge, I'll bet.
303:
386:
516:
816:
For a striking example of this factor, in Google Maps, select satellite view and key in "Yanga, Gladstone South
Australia" then click, once or twice, to a higher view. The winding alignment is the 1880 narrow gauge, the almost straight railway adjacent is a 1970 replacement in standard gauge. And the
769:
In the 19th and early 20th centuries, when most narrow gauge lines were built, commerce was not very time-sensitive. In an age when the alternative mode was animal-hauled, the fact that you could get your freight to its destination with a degree of reliability was the huge competitive advantage. With
715:
Agreed, the information about advantages and disadvantages between narrower gauge and broader gauge railways is not at all clear. And as Bigdan201 said, the information on the net is scattered too. Most of the websites out there seem to provide wrong info regarding comparison. So, as of now, I have
853:
The gauges of railways often have their origins in decisions made in the era of railway development – the second half of the 19th century and early years of the 20th. The choice for any given railway was usually founded not only on the terrain but also on the economic and political history of the
1114:
As I interpret the section on minimum-gauge, it is defined as "smaller than 2 ft, which equals 610 mm". I would rather say "smaller than 2 ft or 600 mm". In Sweden and, I think, other
European countries, there were numerous 600 mm railways built. They had a small gauge, but were not regarded
693:
Digging is right. According to old engineering journals I've read, track gauge does not have a significant relationship with curvature; that it does is a common misconception. Apparently, wider gauge may impose a very slight restriction on turning radius, but for practical purposes it is not
1393:
in Lille where one metro one line seems to be dual track (1435 mm / 1620 mm) while the other line is only 1620 mm. These are Rubber-tyred metro's where tyres run on metal bands wich are 1620 mm apart. Line two has been build without the normal gauge guiding rails. Example:
1076:
Previously today I read in a
Knowledge (XXG) article that the ideas that governments selected track gauge with military defense in mind and that narrower gauges allow for tighter turning radiuses are misconceptions. This paragraph states both. What is the real
838:
How would I encapsulate this? Maybe something like this, which I'll only propose for further discussion and decisions on your part, because it's "top of the head" — I no longer have references to hand on account of being overseas from my
1217:
So if the "1520 mm" is not in the sources for
Finland, your point is right. That is: Finland never metrificated the definition. (Rolling stock is still ordered by the imperial size). Article(s) on Finnish railroads could refine this
926:
be able to calculate at what speed a train would fly of the track or would that take running an automated train on an adequate length of test track? The latter would be a spectacular way to wreck / scrap a train! Trains on
680:
The possible top speed on standard gauge and broad gauge , as determined by the laws of phisics, is the same. at a certain high speed the train tends to literally fly of the rails. This requires a bit of digging.
1369:
Move the sentence about the Battle of the Gauges to be clearer that the following sentence about mountain railways refers to the modern usage of narrow as less than standard, rather than to the
Stephenson gauge?
236:
891:
and heavier engineering. The trade-off is usually their higher speed and tonnage capacity. However, some modern narrow-gauge lines approximate the capacities of broader gauge equivalents. Cheers, Simon.
1395:
865:
The place of political history in the choice of gauge was, in newly developing countries or colonies, related to the gauges already established in the territories of the particular colonial power.
716:
tried to remove conflicting statements and tried to make the section more clearer. Still the section requires good references. Or else for better, the section could be removed altogether.
1427:
858:– the distance between the centres of the front and rear wheels – was shorter, allowing them to negotiate tighter curves. Eventually, development of articulated designs such as the
1154:
Finnish gauge is 1524 mm page 10. It has never been 1520 mm. The change from 1524mm to 1520mm was done in the Soviet Union, and
Finland has never been a part of the Soviet Union.
1457:
530:
694:
meaningful. I certainly never meant to post misinformation, so pardon me for that. It's a tricky topic with scattered information, I'm trying my best to collate it together.
1331:
What about changing the map for a map displaying the
Iberian gauge in the Iberian peninsula (Spain and Portugal), instead of this incorrect map that shows standard gauge?
1462:
795:
So, respectfully, I would argue that "wider gauge may impose a very slight restriction on turning radius, but for practical purposes it is not meaningful" is incorrect.
1437:
452:
230:
525:
348:
1404:. Should we treat this as a 1620 mm track gauge or explain the situation with Rubber-tyred metro's. Luckely there are no other gauges with Rubber-tyred metro's.
162:
1452:
1447:
506:
1472:
462:
876:
that will be removed after short-term use, such as for construction, the logging industry, the mining industry, or large-scale construction projects.
1432:
603:
168:
1048:, a trainee physicist, otherwise known as a locomotive driver, put it in place in February by approaching a 15 km/h turnout at about 80 km/h: see
1049:
1390:
1401:
1134:
I'd say: look at to definition (in sourced) of the "minimum gauge" first. Follow its units, don't extrapolate the definition (to mm's then). -
1467:
1442:
1249:
113:
501:
424:
420:
344:
1332:
127:
182:
187:
103:
1028:
157:
1230:
416:
407:
339:
314:
1214:) (1960). The difference was only 4 millimetres (0.16 in) then, so no rail had to be relaid and rolling stock kept unchanged.
148:
251:
599:
1169:
976:
218:
73:
748:
May I help to clarify a bit? I have experience in planning of high-speed rail lines (though not as a civil engineer).
69:
552:
879:
Broader gauges (especially standard gauge) are generally more expensive to build because characterisitcally larger
273:
268:
192:
1245:
598:
though some data is missing. It would be more accurate and be a good supplement for map already on the page, be
282:
1409:
928:
1316:
320:
1336:
212:
628:
1157:
1355:
624:
872:
work can be substantial. It is also used in sparsely populated areas, with low potential demand, and for
138:
77:
1375:
1124:
208:
1305:
153:
1082:
1234:
994:
685:
657:
302:
1405:
1233:". For the purpose of this article, that is fine (there are some 250 different gauges defined, see
1100:
1057:
1010:
966:
897:
723:
699:
671:
258:
244:
1092:
1078:
287:
573:
1351:
869:
134:
1267:
gauge railways" (bolding added) seeems incorrect, as both sizes are called "Russian gauge". -
1371:
1272:
1165:
1139:
1120:
284:
31:
1119:
design, with light and pre-fabricated pieces, while others were regularly built railways.
1045:
1002:
991:
712:
682:
654:
40:
224:
1096:
1053:
1006:
917:
909:
893:
719:
708:
695:
667:
650:
412:
491:
371:
333:
1421:
1181:
888:
428:
395:
988:
1268:
1238:
1222:
1161:
1135:
961:
880:
873:
618:
107:
1294:
17:
1116:
1095:, Real story seems to be mostly "individual choice". Also see my reply above.
884:
666:
I'm currently researching this again, and editing out info with less support.
642:
543:
868:
Narrow gauge is thus often used in mountainous terrain, where the savings in
923:
855:
638:
1317:
https://www.cia.gov/library/publications/the-world-factbook/fields/384.html
595:
68:) and some terms that are used in it may be different or absent from other
1072:
Conflicting
Information in Paragraph "Gauge selection in other countries"
980:
415:
on
Knowledge (XXG). If you would like to participate, you can visit the
859:
771:
286:
1306:
http://julkaisut.liikennevirasto.fi/pdf4/rato_13_radan_tarkastus.pdf
1413:
1379:
1359:
1340:
1276:
1173:
1143:
1128:
1104:
1086:
1061:
1014:
997:
901:
727:
703:
688:
675:
660:
385:
984:
646:
619:
Track gauge#Advantages and disadvantages of different track gauges
591:
590:, showing the major railways of the world colored by gauge. See
515:
1396:
File:Lille Metro Quatre
Cantons - Grand Stade empty train 2.jpg
1110:
Minimum-gauge – better defined as "less than 2 ft or 600 mm" ?
568:
296:
288:
98:
85:
26:
1027:
It's not difficult to calculate. In fact my late colleague,
572:
542:
514:
490:
411:, an attempt to build a comprehensive and detailed guide to
419:, where you can join the project and/or contribute to the
1192:), then later the definition was changed to metric being
1244:
One might want to check these articles for correctness:
1184:". Russian railroads started defined in Imperial units:
1260:
1256:
862:
allowed powerful locomotives to operate on such track.
357:
243:
1180:"1520 mm" and "1524 mm" are both considered to be "
473:
257:
1295:https://en.wikipedia.org/Rail_transport_in_Finland
1428:Knowledge (XXG) articles that use British English
116:for general discussion of the article's subject.
1350:Why not include 950mm in the list of gauges?--
637:) because the wider gauge would give greater
8:
1400:The other 1620 mm railway line is Orly Val:
1458:High-importance Scotland Transport articles
613:This paragraph contains a lot of conjecture
470:
328:
44:, which has its own spelling conventions (
975:) would probably never reach that speed.
1463:Unreferenced Scotland Transport articles
596:https://wiki.openstreetmap.org/Key:gauge
1438:High-importance rail transport articles
1287:
1259:edit is correct, I will reinstall it.
594:the railroads all have a "gauge" field
330:
300:
1473:Knowledge (XXG) global requested maps
1239:Track gauge § Dominant railway gauges
1150:Finnish gauge is 1524 mm, not 1520 mm
76:, this should not be changed without
7:
1250:History of rail transport in Finland
1241:, Finland should stay in this class.
405:This article is within the scope of
1453:C-Class Scotland Transport articles
1448:Mid-importance UK Railways articles
987:and thus the overall length of the
474:Associated projects or task forces:
319:It is of interest to the following
106:for discussing improvements to the
1044:As for your practical suggestion,
437:Knowledge (XXG):WikiProject Trains
25:
526:WikiProject Transport in Scotland
133:New to Knowledge (XXG)? Welcome!
384:
370:
356:
332:
301:
128:Click here to start a new topic.
30:
1433:C-Class rail transport articles
1252:(has no track gauge mentioned).
1231:5 ft and 1520 mm gauge railways
457:This article has been rated as
1263:removal of Finland from "5 ft
1225:, both sizes are grouped into
592:https://www.openrailwaymap.org
582:It is requested that a global
1:
1277:17:11, 21 December 2020 (UTC)
1174:09:03, 21 December 2020 (UTC)
1115:"minimum". Some were by the
523:This article is supported by
499:This article is supported by
425:WikiProject Trains to do list
125:Put new text under old text.
1468:All WikiProject Trains pages
1443:C-Class UK Railways articles
1380:04:03, 24 October 2022 (UTC)
977:Minimum railway curve radius
1087:21:59, 28 August 2017 (UTC)
440:Template:WikiProject Trains
1489:
1341:11:56, 15 March 2022 (UTC)
1144:18:58, 4 August 2020 (UTC)
1129:17:10, 4 August 2020 (UTC)
463:project's importance scale
1414:12:59, 9 April 2024 (UTC)
1246:Rail transport in Finland
550:
522:
498:
469:
456:
365:
327:
163:Be welcoming to newcomers
92:Skip to table of contents
1360:14:06, 6 June 2022 (UTC)
704:10:43, 8 June 2017 (UTC)
689:01:55, 8 June 2017 (UTC)
676:10:55, 29 May 2017 (UTC)
661:18:25, 18 May 2017 (UTC)
91:
1402:Openrailwap permalink 2
1391:Openrailwap permalink 1
1105:17:02, 1 May 2020 (UTC)
1062:12:26, 2 May 2020 (UTC)
1052:. :-) Cheers, Simon.
1015:07:47, 2 May 2020 (UTC)
998:18:22, 1 May 2020 (UTC)
902:12:26, 2 May 2020 (UTC)
728:17:01, 1 May 2020 (UTC)
502:WikiProject UK Railways
443:rail transport articles
1221:OTOH, in this article
578:
547:
519:
495:
309:This article is rated
158:avoid personal attacks
983:distance between the
576:
546:
518:
494:
313:on Knowledge (XXG)'s
183:Neutral point of view
1327:Iberian gauge on map
188:No original research
74:relevant style guide
70:varieties of English
1346:Italian metre gauge
604:improve its quality
602:in this article to
551:This article lacks
72:. According to the
579:
548:
520:
496:
408:WikiProject Trains
315:content assessment
169:dispute resolution
130:
1160:comment added by
887:mandate a larger
870:civil engineering
623:For example, the
610:
609:
567:
566:
563:
562:
559:
558:
537:
536:
403:
402:
295:
294:
149:Assume good faith
126:
97:
96:
84:
83:
16:(Redirected from
1480:
1319:
1314:
1308:
1303:
1297:
1292:
1213:
1211:
1210:
1206:
1203:
1195:
1191:
1187:
1176:
974:
969:
964:
958:
956:
955:
951:
948:
940:
936:
931:
921:
913:
641:in case of high
636:
631:
569:
481:
471:
445:
444:
441:
438:
435:
388:
379:
378:
374:
367:
366:
361:
360:
359:
354:
351:
336:
329:
312:
306:
305:
297:
289:
262:
261:
247:
178:Article policies
99:
86:
37:This article is
34:
27:
21:
1488:
1487:
1483:
1482:
1481:
1479:
1478:
1477:
1418:
1417:
1387:
1367:
1348:
1329:
1324:
1323:
1322:
1315:
1311:
1304:
1300:
1293:
1289:
1208:
1204:
1201:
1199:
1197:
1193:
1189:
1185:
1155:
1152:
1112:
1074:
979:can affect the
972:
967:
960:
953:
949:
946:
944:
942:
938:
934:
929:
915:
907:
874:temporary lines
634:
629:
615:
531:High-importance
479:
459:High-importance
442:
439:
436:
433:
432:
404:
390:
389:
355:
353:High‑importance
352:
342:
310:
291:
290:
285:
204:
199:
198:
197:
174:
144:
78:broad consensus
41:British English
23:
22:
18:Talk:Rail gauge
15:
12:
11:
5:
1486:
1484:
1476:
1475:
1470:
1465:
1460:
1455:
1450:
1445:
1440:
1435:
1430:
1420:
1419:
1406:Smiley.toerist
1386:
1383:
1366:
1363:
1347:
1344:
1328:
1325:
1321:
1320:
1309:
1298:
1286:
1285:
1281:
1280:
1279:
1253:
1242:
1219:
1215:
1151:
1148:
1147:
1146:
1111:
1108:
1089:John Shanahan
1073:
1070:
1069:
1068:
1067:
1066:
1065:
1064:
1037:
1036:
1035:
1034:
1033:
1032:
1020:
1019:
1018:
1017:
851:
850:
849:
848:
847:
846:
845:
844:
843:
842:
841:
840:
827:
826:
825:
824:
823:
822:
821:
820:
819:
818:
805:
804:
803:
802:
801:
800:
799:
798:
797:
796:
784:
783:
782:
781:
780:
779:
778:
777:
776:
775:
758:
757:
756:
755:
754:
753:
752:
751:
750:
749:
737:
736:
735:
734:
733:
732:
731:
730:
717:
651:standard gauge
622:
614:
611:
608:
607:
580:
565:
564:
561:
560:
557:
556:
549:
539:
538:
535:
534:
521:
511:
510:
507:Mid-importance
497:
487:
486:
484:
482:
476:
475:
467:
466:
455:
449:
448:
446:
413:rail transport
401:
400:
391:
383:
382:
377:
375:
363:
362:
337:
325:
324:
318:
307:
293:
292:
283:
281:
280:
277:
276:
264:
263:
201:
200:
196:
195:
190:
185:
176:
175:
173:
172:
165:
160:
151:
145:
143:
142:
131:
122:
121:
118:
117:
111:
95:
94:
89:
82:
81:
35:
24:
14:
13:
10:
9:
6:
4:
3:
2:
1485:
1474:
1471:
1469:
1466:
1464:
1461:
1459:
1456:
1454:
1451:
1449:
1446:
1444:
1441:
1439:
1436:
1434:
1431:
1429:
1426:
1425:
1423:
1416:
1415:
1411:
1407:
1403:
1398:
1397:
1392:
1385:1620 mm gauge
1384:
1382:
1381:
1377:
1373:
1364:
1362:
1361:
1357:
1353:
1345:
1343:
1342:
1338:
1334:
1333:37.170.58.217
1326:
1318:
1313:
1310:
1307:
1302:
1299:
1296:
1291:
1288:
1284:
1278:
1274:
1270:
1266:
1262:
1258:
1254:
1251:
1247:
1243:
1240:
1236:
1232:
1228:
1224:
1220:
1216:
1183:
1182:Russian gauge
1179:
1178:
1177:
1175:
1171:
1167:
1163:
1159:
1149:
1145:
1141:
1137:
1133:
1132:
1131:
1130:
1126:
1122:
1118:
1109:
1107:
1106:
1102:
1098:
1094:
1090:
1088:
1084:
1080:
1071:
1063:
1059:
1055:
1051:
1047:
1043:
1042:
1041:
1040:
1039:
1038:
1030:
1026:
1025:
1024:
1023:
1022:
1021:
1016:
1012:
1008:
1004:
1001:
1000:
999:
996:
993:
990:
986:
982:
978:
970:
963:
932:
925:
919:
911:
906:
905:
904:
903:
899:
895:
890:
889:loading gauge
886:
882:
881:rolling stock
877:
875:
871:
866:
863:
861:
857:
837:
836:
835:
834:
833:
832:
831:
830:
829:
828:
815:
814:
813:
812:
811:
810:
809:
808:
807:
806:
794:
793:
792:
791:
790:
789:
788:
787:
786:
785:
773:
768:
767:
766:
765:
764:
763:
762:
761:
760:
759:
747:
746:
745:
744:
743:
742:
741:
740:
739:
738:
729:
725:
721:
718:
714:
710:
707:
706:
705:
701:
697:
692:
691:
690:
687:
684:
679:
678:
677:
673:
669:
665:
664:
663:
662:
659:
656:
652:
648:
644:
640:
632:
626:
621:
620:
612:
605:
601:
597:
593:
589:
585:
581:
575:
571:
570:
554:
545:
541:
540:
532:
529:(assessed as
528:
527:
517:
513:
512:
508:
505:(assessed as
504:
503:
493:
489:
488:
485:
483:
478:
477:
472:
468:
464:
460:
454:
451:
450:
447:
430:
429:Trains Portal
426:
422:
418:
414:
410:
409:
399:
398:
397:
396:Trains Portal
392:
387:
381:
380:
376:
373:
369:
368:
364:
350:
346:
341:
338:
335:
331:
326:
322:
316:
308:
304:
299:
298:
279:
278:
275:
272:
270:
266:
265:
260:
256:
253:
250:
246:
242:
238:
235:
232:
229:
226:
223:
220:
217:
214:
210:
207:
206:Find sources:
203:
202:
194:
193:Verifiability
191:
189:
186:
184:
181:
180:
179:
170:
166:
164:
161:
159:
155:
152:
150:
147:
146:
140:
136:
135:Learn to edit
132:
129:
124:
123:
120:
119:
115:
109:
105:
101:
100:
93:
90:
88:
87:
79:
75:
71:
67:
63:
59:
55:
51:
47:
43:
42:
36:
33:
29:
28:
19:
1399:
1388:
1368:
1365:Narrow gauge
1352:Oldboltonian
1349:
1330:
1312:
1301:
1290:
1282:
1264:
1255:I conclude:
1237:). So here,
1226:
1156:— Preceding
1153:
1113:
1091:
1075:
989:rail vehicle
878:
867:
864:
852:
617:
616:
587:
583:
524:
500:
458:
423:. See also:
417:project page
406:
394:
393:
321:WikiProjects
267:
254:
248:
240:
233:
227:
221:
215:
205:
177:
102:This is the
65:
61:
57:
53:
49:
45:
38:
1372:Tom Permutt
1265:and 1520 mm
1223:Track gauge
1121:Fomalhaut76
962:metre gauge
885:locomotives
643:cross winds
349:in Scotland
231:free images
114:not a forum
108:Track gauge
39:written in
1422:Categories
1283:References
1117:Decauville
1003:Peter Horn
992:Peter Horn
924:physicists
713:Peter Horn
683:Peter Horn
655:Peter Horn
577:Map needed
553:references
421:discussion
1235:this list
1097:Vatsmaxed
1054:SCHolar44
1029:Paul Wild
1007:Vatsmaxed
995:User talk
935:3 ft 6 in
918:Vatsmaxed
910:Bigdan201
894:SCHolar44
856:wheelbase
774:article).
720:Vatsmaxed
709:Bigdan201
696:Bigdan201
686:User talk
668:Bigdan201
658:User talk
639:stability
630:5 ft 6 in
171:if needed
154:Be polite
104:talk page
50:travelled
1229:class: "
1194:1,520 mm
1190:1,524 mm
1170:contribs
1158:unsigned
1005:Agreed.
939:1,000 mm
930:1,067 mm
635:1,676 mm
600:included
427:and the
269:Archives
139:get help
112:This is
110:article.
62:artefact
860:Garratt
772:Garratt
627:choose
461:on the
311:C-class
237:WP refs
225:scholar
66:analyse
58:defence
1269:DePiep
1218:point.
1162:Zenfox
1136:DePiep
1093:Fearga
1079:Fearga
1077:story?
985:bogies
968:914 mm
922:Would
434:Trains
340:Trains
317:scale.
209:Google
54:centre
46:colour
1198:4 ft
1050:here
1046:Peter
981:pivot
943:3 ft
839:home:
649:uses
647:eBART
345:in UK
252:JSTOR
213:books
167:Seek
1410:talk
1389:See
1376:talk
1356:talk
1337:talk
1273:talk
1261:This
1257:this
1186:5 ft
1166:talk
1140:talk
1125:talk
1101:talk
1083:talk
1058:talk
1011:talk
973:3 ft
898:talk
883:and
724:talk
711:and
700:talk
672:talk
625:BART
588:maps
453:High
245:FENS
219:news
156:and
1227:one
965:or
937:),
586:or
584:map
259:TWL
1424::
1412:)
1378:)
1358:)
1339:)
1275:)
1248:,
1212:in
1209:32
1205:27
1200:11
1172:)
1168:•
1142:)
1127:)
1103:)
1085:)
1060:)
1013:)
959:)
957:in
914:,
900:)
726:)
702:)
674:)
653:.
645:.
533:).
509:).
480:/
347:/
343::
239:)
137:;
64:,
60:,
56:,
52:,
48:,
1408:(
1374:(
1354:(
1335:(
1271:(
1207:⁄
1202:+
1196:(
1188:(
1164:(
1138:(
1123:(
1099:(
1081:(
1056:(
1009:(
971:(
954:8
952:⁄
950:3
947:+
945:3
941:(
933:(
920::
916:@
912::
908:@
896:(
722:(
698:(
670:(
633:(
606:.
555:.
465:.
431:.
323::
274:1
271::
255:·
249:·
241:·
234:·
228:·
222:·
216:·
211:(
141:.
80:.
20:)
Text is available under the Creative Commons Attribution-ShareAlike License. Additional terms may apply.
