Effect of pre-drilling, loading rate and temperature variation on the behavior of railroad spikes used for high-density-polyethylene crossties

Abstract

Railroad spikes represent a vital component of the rail track system, as they fasten the rail to the supporting crossties. Thus, it is important to understand its behavior and effect on the fastening assembly to mitigate any local failure, which, in turn, could lead to system deterioration or damage. Currently, alternative solutions to the traditional hardwood timber crossties are increasing being adopted by the railroad industry in the USA, with recycled plastic composite crossties being among the available alternatives. Their sustainably, environmental benefits, durability and ease of installation render them an attractive and competitive solution. Several research programs have studied this material and its fastening system in the past; however, additional research is required to fully understand the behavior of these materials and their interactions with the fastening system components. This paper presents an investigation that aims to understand and assess the performance of typical railroad spikes used for recycled high-density-polyethylene crossties. The study encompassed a comprehensive experimental investigation and analytical finite element modeling. The testing program evaluated railroad spikes using static testing methods recommended by the American Railway Engineering and Maintenance-of-Way Association (AREMA) manual. These tests addressed the rail spike pullout and lateral restraint for both screw and cut spikes. Finite element models were constructed and calibrated using the data obtained from the experimental program in order to extrapolate on the experimental results and predict the behavior of full-scale systems beyond the scale of the laboratory. The results observed in this study showed great promise, surpassing all the AREMA recommendations, which highlights the potential of these materials if properly optimized and engineered. Screw spikes exhibited a very good performance, surpassing the minimum recommendations by a significant margin (up to more than 200%) and are thus are highly recommended for future implementation.

Evaluation of the longitudinal restraint, uplift resistance, and long-term performance of high-density polyethylene crosstie rail support system using static and cyclic loading

“…The screw spikes were installed manually using an adjustable wrench with the predrilling configuration proposed by the authors in the previous study: ''setup D'' profile. 18 Seeing as the testing machine can only apply vertical loading, the specimens were rotated 90 and were fixed on their side in order to achieve the desired testing configuration. A wide flange steel I-beam was cut into a 24 in.…”

“…The systems uplift resistance is provided by both the fastening clips and the screw spikes pullout resistances. Since the screw spikes pullout resistance was already investigated in previous tests, 18 this test will enable the assessment of the fastening clips pullout resistance as well as the identification of the contributions of the screw spikes and the fastening clips to the pullout resistance of the entire system. For this test, the crosstie specimens were cut into 3 ft (0.91 m) long segments and the rail was cut into a 20 in.…”

“…16,17 Additionally, a parametric experimental investigation was also conducted to assess the effect of predrilling, loading rate, temperature, and type of spike on the behavior of rail fastening spikes. 18 In this paper, the behavior of the entire system is being investigated using recommendations from the previous work. This paper presents an experimental investigation aiming to understand and assess the performance of the full rail support system, i.e.…”

“…The complete rail and fastening system assembly was installed using the recommended setup D predrilled pilot holes as mentioned earlier. 18 Two steel channels section were used in order to fix the specimens to the testing bed when applying the vertical uplift loading. A 20 in.…”

“…The complete rail and fastening system assembly was installed using setup D predrilled pilot holes as mentioned earlier. 18 The specimens were then mounted on an inclined rigid reaction steel frame with supporting angles encasing them for the sides and the bottom. The steel frame was manufactured with an inclination angle of 22° to simulate, using only one actuator, the vertical and horizontal components of the rail wheel loading, which yields a lateral to vertical load ratio of 0.4 (L/V = 0.4).…”