軌枕在鐵路系統中扮演著舉足輕重的角色，負責固定軌距、維持軌道線形以及將輪軸傳遞的載重分散於道碴上等功能。儘管近年來臺鐵逐步汰除木枕，新式軌道建設多採用PC枕，木枕尚存在於臺鐵許多路線。然而，木枕易受到生物和環境因素影響其品質，若不經常巡視，容易疏忽已經腐朽的木枕。
本研究主要探討木枕道釘拉拔力，起初參考國外文獻瞭解相關內容，也於本系結構材料實驗室進行不同型式道釘在完好木枕中的拉拔實驗。除了完好木枕以外也想瞭解不同腐朽程度木枕道釘拉拔情況，因此與臺鐵現地工程師請教木枕腐朽程度的分類方式，由優至劣分為四個等級，進一步設計道釘拉拔實驗儀器，於臺鐵臺南站側線對不同程度木枕進行道釘拉拔。得到完好的木枕拉拔力遠超越其餘等級，其餘等級彼此間差距不大的結果。最後利用現地拉拔力數據結合結構分析軟體STAAD/Pro應用在2017年普悠瑪列車於三民站的脫軌事故調查。結果顯示，當脫軌係數超越0.7除了完好狀態的木枕道釘拉拔力還在限度內，其餘較差等級的木枕皆會超越其最大拉拔力，佐證道釘拉拔力確實在脫軌事故扮演關鍵的角色。

There is no denying that sleepers play an important role in railway system. Sleepers are responsible for spreading the loading from bogie to ballast. Although TRA (Taiwan Railways Administration) uses PC (Prestressed concrete) sleepers instead of timber sleepers in recent years, they still exist in the routes. However, timber sleepers are vulnerable to environment, should be inspected regularly and replaced with a new one if necessary.
In this research, we focused on the holding power of rail spikes on deteriorated timber sleepers and two parts would be done. The first part is experiments and the second part is computer simulation relative to Puyuma Express derailment accident happened in 2017 at Sanmin Station, Hualien.
The experiments would be performed in ETM-Lab(Engineering Technology and Material Laboratory), NCKU and TRA Tainan station respectively. For the experiment in ETM-Lab, we tested the holding power of rail spikes on intact timber sleepers. Additionally, tried to grade four level of timber sleepers depended on how worse they were and would be chosen to perform holding power test of rail spikes in TRA Tainan station.
As a result, we found that the holding power of rail spikes on intact timber sleepers was much greater than those on deteriorated timber sleepers. Last but not least, the results of experiment in TRA Tainan Station would be imported into computer simulation in order to evaluate the risk of the derailment. The results showed that if the derailment coefficient was greater than 0.7, the holding power of rail spikes will be greater than the results derive from experiment except for the rail spikes on intact timber sleepers.

[1] 交通部鐵路營運監理小組, "臺鐵正線出軌事故專案調查辦理情形," 2017.
[2] 交通部鐵路營運監理小組, "交通部鐵路重大事故專案調查報告," 2018.
[3] R. I. Webber, "Holding power of railroad spikes," University of Illinois at Urbana Champaign, College of Engineering. Engineering Experiment Station.1906.
[4] A. H. Beyer, Tests on the Holding Power of Railroad Spikes. Civil Engineering Testing Laboratories, Columbia University, 1919.
[5] W. Ferdous and A. Manalo, "Failures of mainline railway sleepers and suggested remedies – Review of current practice," Engineering Failure Analysis, vol. 44, pp. 17-35, 2014/09/01/ 2014.
[6] S. Yella, M. Dougherty, and N. K. Gupta, "Condition monitoring of wooden railway sleepers," Transportation Research Part C: Emerging Technologies, vol. 17, no. 1, pp. 38-55, 2009/02/01/ 2009.
[7] S. Corporation. UH-50A. Available: http://www.mts.com/en/index.htm
[8] N. D. Inc. Optotrak Certus. Available: https://www.ndigital.com/msci/products/optotrak-certus/
[9] 交通部臺灣鐵路管理局, "台灣鐵路財務規範-防腐木枕," 2015.
[10] D. W. Green, J. E. Winandy, and D. E. Kretschmann, "Mechanical properties of wood," Wood handbook: wood as an engineering material. Madison, WI: USDA Forest Service, Forest Products Laboratory, 1999. General technical report FPL; GTR-113: Pages 4.1-4.45, vol. 113, 1999.
[11] L. OPTEX FA CO. CD33-120N(P)V. Available: https://www.optex-fa.com/
[12] T. S. Kenkyujo. CLG-NB Compression Load Cell. Available: http://www.tml.jp/e/product/transducers/general/load_cell/compress/clg.html
[13] N. T. S. Board, "Derailment of WMATA Metrorail Train in Interlocking Falls Church, Virginia," 2017.
[14] 臺鐵局行保會, "交通部鐵路重大事故調查第21次會議," 2017.
[15] 黃清景, "交通部臺灣鐵路管理局行車事故報告書," 2017.
[16] 交通部鐵路營運監理小組, "106年11月9日辦理臺鐵三民站出軌專案調查現勘缺失," 2017.
[17] 交通部, "1067 公厘軌距鐵路長焊鋼舖設及養護規範," 1997.
[18] 桃谷尚嗣, "移動荷重の影響を考慮した鉄道路盤の変形特性に関する研究," 東京大学, 2004.
[19] 鉄道総合技術研究所, "鉄道構造物等設計標準・同解説 省力化軌道用土構造物," 1999.
[20] B. J. Van Dyk, M. S. Dersch, J. R. Edwards, C. J. Ruppert Jr, and C. Barkan, "Evaluation of dynamic and impact wheel load factors and their application for design," in Transportation Research Board 93rd Annual Meeting, 2014, no. 14-4714.