LINE C, LONG ISLAND.

--------------+-----------------+-------------------+-------------------------+

| | Station: | Date: |

| |---------+---------+------------+------------+

| | | | | |

Material. | Method. | From | To | From | To |

--------------+-----------------+---------+---------+------------+------------+

All rock |Bottom heading | 68+61.9 | 69+93 |June 11, '06|Oct. 16, '06|

| | | | | |

Earth and rock|Bottom heading | 69+93 | 71+65 |Oct. 16, '06|Feb. 7, '07|

| | | | | |

All rock |Bottom heading | 71+65 | 71+91 |Feb. 7, '07|Feb. 13, '07|

| | | | | |

All rock |Center heading | 71+91 | 75+81 |Feb. 13, '07|July 20, '07|

| | | | | |

Earth and rock|Going out of rock| 75+81 | 76+56 |July 20, '07|Aug. 25, '07|

| | | | | |

All earth |Soft ground | 76+56 | 90+44.4 |Aug. 25, '07|Mar. 17, '08|

--------------+-----------------+---------+---------+------------+------------+

--------------+------+--------+--------+--------------------------------------+

| | |Rate of | |

|Number| |progress| |

| of | Linear |in feet | |

Material. | days.| feet. |per day.| Remarks |

--------------+------+--------+--------+--------------------------------------+

All rock | 127 | 131.1 | 1.03 | |

| | | | |

Earth and rock| 114 | 172 | 1.51 | |

| | | | |

All rock | 6 | 26 | 4.33 | |

| | | | |

All rock | 157 | 390 | 2.48 | |

| | | | |

Earth and rock| 36 | 75 | 2.08 | |

| | | | |

All earth | 205 |1,388.4 | 6.77 | |

--------------+------+--------+--------+--------------------------------------+

Transactions of the American Society of Civil Engineers, vol. LXVIII, Sept. 1910 The New York Tunnel Extension of the Pennsylvania Railroad. The East River Tunnels. Paper No. 1159 · 第 21 / 35 题