Vibration Mitigation Effect Investigation of a New Slab Track Plate Design

This study proposed a novel vibration mitigation slab track plate design to mitigate the vibration induced in urban rail transit operations. The optimal recipe for the newly designed slab track plate is obtained by a series of laboratory tests, and both newly designed vibration mitigation slab track plates and normal slab track plates are fabricated and hereinafter tested. The newly designed slab track plate was examined with a series of laboratory tests in comparison with the normal slab track plate. The PolyMAX method is then adopted for extracting the modal properties, including resonant frequencies, and damping ratios are also determined for both the designed slab and normal slab track plates. A vibration mitigation level (Ls) is defined to address the vibration mitigation performance taking the acceleration response of the normal slab track plate as reference. The newly designed slab track plate demonstrated better dynamic and damping characteristics in comparison with the normal slab track plate. Under the same excitation force, the newly designed slab track plate can mitigate 8.9 dB on average in the frequency range [20, 400] Hz, expressing the feasibility of effective vibration mitigation capacity.

Research on the Longitudinal Displacement between Track Plate and Filling Layer under the Influence of Temperature

In the construction process, it is not a one-time work to complete the track plates overall longitudinal connection of the CRTSII ballastless track structure. Moreover, due to the tracks longitudinal connection, temperature difference can form displacement accumulation in the whole structure. Under some serious circumstances, it may even produce excessive longitudinal displacement between track plate and mortar layer, and make mortar layer void. Based on the finite element method, a finite element model is built on the track plate and mortar layer. By targeting at the free end of the track plate, carry on a stress displacement analysis; study the influence of changeable temperature on motor layers relative displacement with track plate,the reasonable construction temperaturefor construction is put forward. The research results provide references for the ongoing ballastless track construction on the passenger dedicated line.

A Direct Comparison of Enclosed Track Plates and Remote Cameras in Detecting Fishers, Martes pennanti, in North Dakota

Fishers (Martes pennanti) historically were reported to occupy forested areas of northeastern North Dakota, but the population was presumed extirpated during the 1900s as a result of overtrapping. Recently (≤15 years), Fishers have been recolonizing the state, and there is increasing interest in developing approaches for monitoring the population. During the period June–August 2008, we compared the efficacy of remote cameras and enclosed track plates in detecting Fishers in riparian forest along portions of the drainage basin of the Red River of the North in eastern North Dakota. We monitored 122 scent stations, each composed of both detection devices, with the remote camera positioned to monitor the entrance of the enclosed track plate. Fishers were detected at 40 of the 122 scent stations (32.8%) distributed along approximately 790 km of riparian forest. Among those 40 stations, Fishers were detected by both camera and track plate at 28 stations (70.0%), by camera only at 9 stations (22.5%), and on track plates only at 3 stations (7.5%). Overall, Fishers were detected 37 times by camera (92.5%) and 31 times on a track plate (77.5%). From photographic evidence at the 37 stations where Fishers were detected by camera, we determined that the average latency to initial detection was 4.8 days (SE 0.3, range 1–8). Among the 37 stations where Fishers were detected by camera, detections most frequently occurred on one (27 sites) (73.0%) or two days (7 sites) (19.0%) of a detection period.

New Type of Cantilever Crane for High-Speed Railway Track Plate Constructions

In China, the high-speed railway construction is growing rapidly currently. As laying the high-speed railways’ track plates accurately is an important part of construction, a large number of multifunctional advanced special cranes are required in order to complete the construction task on time. In the paper, the advanced design and application of the new type large cantilever special crane, which being used in the high-speed railway track plate constructions of Jinghu railway, Huning railway and Guangshengang railway, is introduced. The special main characteristics of the new type multifunctional large cantilever are described, such as easy to be assembled, easy to change the span, the cantilever beams can being folded, can being used in the tunnel, and so on. The successful applications of the new type crane have solved a number of difficulties in the track plate constructions, and have obtained obvious economic returns and social returns.

Developing relative abundance techniques (RATs) for monitoring rodent populations

Accurate density estimates of rodents are frequently difficult or cost-prohibitive to determine. Thus, a number of techniques (track plates, monitoring blocks, chew cards/sticks, apple slice index, trapping) are often used to index rodent populations. Theoretically, the sensitivity of these indexing techniques could be improved if they applied continuous measurements rather than simple binary measurements (presence/absence). Development of a relative abundance technique that is simple to apply and sensitive to changes in population density is critical for the operational management of rodent pests. In addition to providing a quantitative measure of abundance with statistical parameters, an indexing technique that does not require handling of animals is important in consideration of potential disease issues (for example, hantavirus, arenavirus, etc.). We investigated track plates, chew cards and monitoring blocks and associated continuous measurement methods for calculating indices of rodent abundance. In laboratory and field settings, we tested their effectiveness in detecting different population densities of California meadow voles (Microtus californicus). Chew cards were poorly accepted by meadow voles in pen and field tests. However, track plates and monitoring blocks may provide useful tools for indexing meadow vole populations, and have application for other rodent species.