Tie replacement estimate, Kestrel Subdivision MP 112.40–123.55
Parametric estimate for replacing 3,013 ties in the 2027 tie program. Ties, OTM, ballast, scrap ties, man-hours and work windows are worked out from tie counts, overage, window length and gang size. With 5-hour windows and an 8-laborer gang the estimate comes to $276 per tie, $830,496 over 28 windows.
Tie inspection, Oct 2026Kestrel Valley Railroad, Kestrel Subdivision MP 112.40–123.553,013 ties in 4 segments2026 ratesPrepared Nov 5, 2026
Summary
Window length
7-hour windows bring the cost down to $259 per tie
Every window loses 80 minutes to the job briefing, track authority, setting on and clearing the equipment. In a 4-hour window 67% of the time produces ties; in a 7-hour window 81%. Going from 4 to 7 hours cuts the job from 39 to 19 windows and labor, equipment and mobilization per tie by 33%, $121,712 on the job. Work_Window_Plan_Kestrel_Sub_2027.pdf (p. 3) plans 5 hours.
Next step: ask the railroad whether the windows can be combined into fewer, longer ones.
Gang size
The eighth laborer adds no production
The tie inserter handles 32 wood ties an hour and seven laborers keep up at 35, so an eighth does not raise the rate. With 7 the job still takes 28 windows and costs $12,544 less, $271 per tie. With 6 the gang becomes the bottleneck and the job needs 30 windows (Estimating_Rates_Track_2026.xlsx, Production sheet).
Next step: crew the wood tie segments with 7 laborers.
Segment 4
The last 4 concrete ties cost a full window
Brittlebush–Saltcedar has 268 cracked concrete ties. The inserter handles 24 concrete ties an hour, 88 per 5-hour window, so three windows cover 264. The 4 left over need a fourth window costing $10,798 (Tie_Inspection_Kestrel_Sub_MP112-124.xlsx, MP 120–124 sheet).
Next step: ask for one window on the segment 10 minutes longer, which covers the 4 ties.
Tie program estimate model
Change window length, gang size, inserter rate, overage and mobilization with the sliders, or tie counts by segment in the table. Unit costs are compared with the base estimate. The calculation chain shows how each value is derived and the sensitivity tab which input moves the cost per tie most.
of which 80 min fixed per window
affects calendar time only
plus foreman, RWIC and 2 operators
concrete ties at 75% of this rate
on ties, OTM and ballast
equipment move, set-on, protection
AREMA No. 4A, delivered
Cost per tie–
Total cost–
Ties per track hour–
Man-hours per tie–
Work windows–
Production and windows by segment
Segment
Tie type
Ties
Rate, ties/h
Limited by
Per window
Windows
Last window
Man-hours
Per tie
Windows by segment
Each box is one work window, filled by the share of productive time used. A nearly empty last window costs as much as a full one.
Full windowLast window under 25% used
Man-hours by craft
Craft
In gang
Rate
Man-hours
Per tie
Material to order
Overage is applied to ties, OTM and ballast. OTM quantities are rounded up by item. Rail anchors average 2 per tie, box anchored every other tie.
Item
Per tie
Net
Overage
Order
Unit price
Amount
Scrap from removed ties
Weight per removed tie: wood 200 lb, concrete 700 lb. Cost covers pickup along the right-of-way ($6 per tie) and disposal including haul.
Material
Count
Weight, tons
Handling
Cost
Scrap creosote ties.Used creosote-treated ties are not a listed hazardous waste and are generally non-hazardous unless contaminated, but the generator still makes the waste determination. Separately, ties that are processed and burned in qualifying units are a categorical non-waste fuel under 40 CFR 241.4(a)(7). The estimate carries $85 per ton for grinding and haul per Tie_Disposal_Quote_2026.pdf. Confirm the disposal route with the receiving facility and ADEQ before award.
Cost by category
Category
Amount
Per tie
Share
Change per tie
Cost per tie by segment
Segment
Ties
On-track work
Total
On-track work is labor, equipment and mobilization per tie. Concrete ties cost more to buy and take longer to install per tie.
Calculation chain from inputs to unit costs
The model's cells with formulas and current values. Click a row to see which cells it depends on and which cells use it.
Depends onUsed in123Input from the sliders
Cell
Description
Formula
Value
Which input moves the cost per tie most
Cost per tie vs. window length
Cost per tieLabor, equipment and mobilization per tie
Sources and method
Sources
Tie_Inspection_Kestrel_Sub_MP112-124.xlsxTie condition survey, Oct 2026: defective ties by milepost, tie type and segment3,013 ties
Tie_Program_Estimate_Model_v3.xlsxThe estimate model: Inputs, Time, Quantities, Cost and UnitCost sheets5 sheets
Estimating_Rates_Track_2026.xlsxBurdened labor rates, equipment rates, material prices and production rates2026 rates
Work_Window_Plan_Kestrel_Sub_2027.pdfPlanned work windows between scheduled trains: 5 hours, 4 days a week6 pages
Tie_Disposal_Quote_2026.pdfScrap tie pickup, grinding and haul; concrete tie disposal3 pages
Method
Tie counts by segment and tie type were taken from the tie condition survey.
The production rate on each segment is the lower of the gang rate (laborers × production per laborer) and the tie inserter rate. Concrete ties run at 75% of the wood tie inserter rate.
Productive time per window is the window length less 80 minutes of fixed time. Windows are rounded up by segment, because track authority is requested between control points.
Man-hours and labor cost use paid time, window length plus 2 hours per person per window. Equipment time is window length plus 1 hour.
Material includes overage on ties, OTM and ballast. Scrap tie disposal is figured per removed tie from weight, disposal price and pickup.
Sensitivity moves one input at a time to its low and high value while all others keep their current values.
Assumptions and limitations
Rates per Estimating_Rates_Track_2026.xlsx. No escalation, contingency or sales tax. Rate levels have not been checked against current quotes and should be confirmed by the estimator.
The RWIC is carried in the contractor's crew. The railroad's on-track safety rules may require its own RWIC or flagman instead; the estimator should confirm this in the contract.
Every replacement tie gets new tie plates, spikes and anchors, or new clips, pads and insulators on concrete. Reusing plates would lower material cost.
Scrap plates, spikes and clips are shown as scrap metal with no credit. Used pads and insulators go with the scrap concrete ties.
Unused time in a window is not carried over to another segment, and each window is charged in full.
Windows per Work_Window_Plan_Kestrel_Sub_2027.pdf. No time is carried for waiting on trains or track authority.
Surfacing behind the gang is a subcontract per tie. Track inspection after the work is done by the railroad and is not included.
This is a parametric estimate and does not replace a detailed estimate.