racing (up/down alternation) for 180s
ss=115866 at=24686 dt=24690
ss=267917 at=57547 dt=57553
ss=405132 at=85181 dt=85187
ss=623747 at=126147 dt=126162
ss=821244 at=161405 dt=161435
ss=995427 at=195347 dt=195382
ss=1159562 at=230086 dt=230134
ss=1316211 at=265377 dt=265427
ss=1602046 at=314049 dt=314119
ss=2253808 at=424038 dt=424130
ss=2523938 at=465882 dt=465979
ss=2825352 at=519404 dt=519517
ss=3192888 at=574555 dt=574603
ss=3459586 at=627603 dt=627663
ss=3928131 at=704086 dt=704174
ss=4037710 at=725665 dt=725757
ss=4396380 at=784660 dt=784756
ss=4713463 at=838996 dt=839102
ss=5047581 at=891965 dt=892056
ss=5296890 at=933159 dt=933250
ss=5512318 at=970607 dt=970701
ss=5803015 at=1022316 dt=1022430
ss=6125998 at=1075274 dt=1075393
ss=6493165 at=1142591 dt=1142724
ss=6625123 at=1172608 dt=1172742
ss=6846474 at=1216921 dt=1217066
ss=7115516 at=1264983 dt=1265133
ss=7192666 at=1291555 dt=1291715
ss=7305302 at=1311074 dt=1311249
ss=7495888 at=1346194 dt=1346374
ss=7664863 at=1375063 dt=1375248
ss=8170011 at=1462016 dt=1462215
ss=8368814 at=1492108 dt=1492309
ss=8543515 at=1525772 dt=1525972
ss=8740853 at=1558861 dt=1559075
ss=8902932 at=1588977 dt=1589184
SURVIVED ss=8902936 at=1588979 dt=1589187