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Record W2056724241 · doi:10.1115/jrc2010-36050

Spiral Length Design

2010· article· en· W2056724241 on OpenAlexaff
Nazmul Hasan

Bibliographic record

Venuenot available
Typearticle
Languageen
FieldEngineering
TopicRailway Engineering and Dynamics
Canadian institutionsSNC-Lavalin (Canada)
Fundersnot available
KeywordsSpiral (railway)Rotation (mathematics)Elevation (ballistics)JerkAccelerationMathematicsGeometryTwistCurrent (fluid)PhysicsMathematical analysisGeodesyClassical mechanicsGeology

Abstract

fetched live from OpenAlex

Most of the current formulae for spiral length use either unbalance, Eu or actual super-elevation, Ea to calculate spiral length, L as applied to light rail, commuter rail, and rapid transit. In reality, a train suffers both Eu and Ea run-off simultaneously. Super-elevation unbalance run-off produces the effect of radial acceleration and actual super-elevation run-off produces the effect of rotation. As a result due to this spiral length design should be based on both Ea and Eu. The current formulae underestimate spiral length which affects comfortable jerk rate, roll criteria, and twist rate. These formulae do not shed any light on how to proportion actual and unbalance superelevation to realize desired results. Consequently from these formulae, desirable values of Ea and Eu cannot be calculated, so it is necessary to re-evaluate the current formulae. It is mathematically established that combined effects of Ea and Eu run-off set a limit of 45mm/sec. A new formula for spiral length comes out to be: L = 0.006(Ea+Eu)V. But this formula does not reflect the effect of proportion of Ea and Eu. This gives the same length whatever be the proportion of Ea and Eu. To overcome this deficiency a second formula is derived as: L=VEa161−Eu. The article analyzed the effect of proportion of Ea and Eu on spiral length. The formulae developed in the paper satisfy both cant gradient and rotation criteria that are currently used. If these formulae are used, these criteria do not require checking. The analysis reveals the basis of cant gradient that is to be used for spiral length design. As extensions of these new formulae are developed for minimum spiral length, minimum length of circular curve, rate of twist, maximum safe speed etc. For Heavy haul operation issues of over-loading and off-loading on the twisted track is also discussed to review cant gradient for spiral length design.

Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.

How this classification was reachedexpand

Full frame distilled prediction

Teacher imitation

Not calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.

metaresearch head score (Codex)0.000
metaresearch head score (Gemma)0.000
Version: codex-gemma-dda1882f352aValidation status: machine_predicted_unvalidated
Candidate categoriesnone
Consensus categoriesnone
DomainCandidate signal: none · Consensus signal: none
Study designCandidate signal: Simulation or modeling · Consensus signal: Simulation or modeling
GenreCandidate signal: Empirical · Consensus signal: none
Teacher disagreement score0.743
Threshold uncertainty score0.261

Codex and Gemma teacher scores by category

CategoryCodexGemma
Metaresearch0.0000.000
Meta-epidemiology (narrow)0.0000.000
Meta-epidemiology (broad)0.0000.000
Bibliometrics0.0000.000
Science and technology studies0.0000.000
Scholarly communication0.0000.000
Open science0.0000.000
Research integrity0.0000.000
Insufficient payload (model declined to judge)0.0000.000

Machine scores (provisional)

The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.

Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.

Opus teacher head0.008
GPT teacher head0.184
Teacher spread0.176 · how far apart the two teachers sit on this one work
Validation statusscore_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from it

Classification

machine, unvalidated

Machine predicted; a candidate call from one teacher head, not a consensus.

The models applied no category: nothing in the taxonomy fit this work.
Study designSimulation or modeling
Domainnot available
GenreEmpirical

How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".

Quick stats

Citations3
Published2010
Admission routes1
Has abstractyes

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