tram cb analysis tech report

Technical ReportTramway Cost Benefit Analysis

Prepared for

Roosevelt Island Operation Corporation591 Main StreetRoosevelt Island, New York 10044

Prepared by

Parametrix Consulting, Inc.1331 Seventeenth Street, Suite 606Denver, CO 80202-1589303-791-9235www.parametrix.com

http://www.parametrix.com/

CITATION

Parametrix Consulting, Inc.. 2007. Technical ReportTramway Cost Benefit Analysis. Prepared by Parametrix, Denver, Colorado.

December 10, 2007.


Roosevelt Island Operation Corporation

December 10, 2007 │ 354-5162-002 (01/11) i

TABLE OF CONTENTS

1. INTRODUCTION AND SUMMARY.................................................................. 1-12. PURPOSE AND BACKGROUND.................................................................... 2-13. LIFE CYCLE COSTS....................................................................................... 3-14. RIDERSHIP AND REVENUE ESTIMATES ..................................................... 4-15. DOWN TIME ESTIMATES............................................................................... 5-16. NET REVENUE AND COST PER RIDER........................................................ 6-17. NON-QUANTIFIABLE FACTORS ................................................................... 7-18. CONCLUSIONS .............................................................................................. 8-1

LIST OF FIGURES1 Annualized Cost Estimates ($ 2007) ................................................................... 3-3

2 Ridership Trends by Fiscal Year ......................................................................... 4-1

3 Fare Revenue Trends by Fiscal Year................................................................... 4-2

4 Ridership Trends by Month ................................................................................ 4-2

LIST OF TABLES1 Annualized Cost Estimates ($ 2007) ................................................................... 3-3

2 Estimates of Annual Down Time and Replacement Times .................................. 5-1

3 Net Revenue Per Rider ....................................................................................... 6-1

4 Net Revenue Per Rider Sensitivity Analysis........................................................ 6-2



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1. INTRODUCTION AND SUMMARYThis Technical Report documents the findings and conclusions of an analysis undertaken todevelop information on the benefits and costs of the alternatives now under consideration bythe Roosevelt Island Operating Corporation (RIOC) for the rehabilitation and/or replacementof the tramway that connects Roosevelt Island to Manhattan. This tramway has been inservice for over 30 years and is now at a stage where a major investment may be required ifthis lifeline to the island is to remain a reliable and dependable mover of people. Theapproach taken in the analysis was to develop life cycle cost estimates for the alternativesunder study and then compare these costs to passenger revenues and ridership estimates togain an understanding of the relative magnitude of the cost and revenue per rider. Theanalysis results demonstrate that within the range of the options being considered all fouralternatives would produce highly efficient investments to move people to and from theisland, and that the per passenger revenue and cost differences among the alternatives arerelatively small. Thus, the primary considerations in choosing an alternative become the morenon-quantifiable benefits. These non-quantifiable benefits include the means of rescue in theevent of system failure, system reliability and dependability, passenger service flexibility andADA access (access for the mobility impaired).



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2. PURPOSE AND BACKGROUNDParametrix has completed detailed studies for the Roosevelt Island Operating Corporation(RIOC) to identify the best way to modernize the Roosevelt Island Tramway so that it mayprovide another 25 years, or more, of reliable service between Roosevelt Island and midtownManhattan. Findings of this work are documented in a Preliminary Engineering Reportprepared in March of 20071. This report identified four basic approaches to modernizing theTramway, as follows:

Alternative 1 – Replace Critical SubsystemsThis option was developed for the purpose of providing a baseline, since doing nothing is nota legitimate option. This alternative includes the replacement of the track ropes, cabinhangers, cabins and track rope roller chains. Other than the required modifications, thesystem would remain as it is today. In the event of a major component failure, the systemcould be out of operation for a lengthy period of time. This alternative would make nomodification to the rescue system. Therefore, in the event of a major system failure whichrenders the tramway inoperable, a long and arduous evacuation may be necessary. Assumingthat the replacement components could be timed so that they are all available on site at once,it is estimated that the system would be out of operation for approximately 8 weeks toaccomplish the rehabilitation. This alternative does not provide a high level of confidence foran additional 25 years of service. While the life expectancy of this alternative is difficult topredict, a reasonable mid-range assumption is that within 7 years additional major workwould be needed to keep the tramway in reasonable operating condition. With thisalternative, additional failures or issues should be expected resulting in unknown additionalcosts and downtimes.

Alternative 2 – Replace with Similar TramwayThis alternative would replace the system as it is today with approximately the samearrangement, but with the latest available technologies. The existing motors and drives wouldbe replaced with new AC components. A new gearbox and drive train would be installed. Therescue tram would be modified or replaced to facilitate its mobilization and operation, but thegeneral premise of a separate rescue tramway would remain. This alternative could bereasonably expected to provide another 25 years of service, or more. It is expected that thesystem would be inoperable for approximately 6 months during the replacement

Alternative 3 – Replace with Similar Tramway, Add RedundancyThis alternative is one step beyond the previous alternative. It amounts to installing a new butsimilar tramway, doing so with currently accepted technologies and designing additionalredundancy into the system. The additional redundancy would be designed to provide a highlevel of availability and to potentially provide an integrated rescue approach. The additionalredundancy would be achieved by installing multiple elements such two gearboxes, two ACdrives and two AC motors in a way that they could be readily put into service. If theintegrated rescue is achieved, the rescue tram could be eliminated. If not, the rescue systemwould be upgraded or replaced to improve its efficiency. This alternative could reasonably beexpected to provide another 25 years, or more, of service. It is expected that the system wouldbe out of operation for approximately 7 months during the replacement.

1 Tramway Modernization Preliminary Engineering, Roosevelt Island Operating Corporation,Parametrix Consulting, March 2007.

Technical ReportTramway Cost Benefit AnalysisRoosevelt Island Operation Corporation

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Alternative 4 – Replace with Dual Shuttle OperationThis alternative would replace the tramway system with a dual shuttle system. Fundamentallythis means having two tramways side by side, which operate independently from each otherexcept that they share towers, terminals and operations personnel. This arrangement allowsthe greatest flexibility in operations and maintenance scheduling. One system may be shutdown for maintenance while the other system continues to operate and serve passengers. ADual Shuttle system could reasonably be expected to provide at least another 25 years ofservice and at the highest availability level of the alternatives evaluated. It is estimated thatthe system would be out of operation for approximately 7 months.

To assist the Roosevelt Island Operating Corporation (RIOC) in reaching decisions on themost cost effective approach to the rehabilitation and/or reconstruction of the RooseveltIsland Tramway, an analysis that identifies both the costs and benefits of the alternativescurrently under consideration was undertaken. Capital cost estimates for these alternativesrange from $5 to $20 million ($ 2007). Of these alternatives, the long term choices are reallyamong the last three, since Alternative 1 consists of only short-term actions necessary toaddress the most immediate issues. Therefore, Alternative 1 was used as the baseline for thecomparison of Alternatives 2, 3 and 4.

The approach to analyzing costs and benefits was performed in two steps. The first stepdeveloped an annual net revenue or cost per passenger for each alternative and was based onthe best available estimates of life cycle costs, ridership and fare revenue. The approach usedis consistent with similar types of analyses performed to assess alternative investments in thepublic transit industry. The second step then identified the potential non quantifiable benefitsof each of the alternatives including the means of rescue in the event of system failure,system reliability and dependability, passenger service flexibility and ADA access (access forthe mobility impaired). In all cases, Alternative 1 was used as the basis for comparison ofcosts and benefits.



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3. LIFE CYCLE COSTSThe development of life cycle costs was the first step in the analysis. The purpose of the lifecycle cost analysis is to provide a means of identifying all costs over the life of the systemand a basis for comparing the cost of alternatives that have different capital investments aswell as on-going maintenance and operations costs. The end product is what is known as anannualized cost which represents the average cost per year over the expected life of theinvestment. For the purpose of this analysis everything was done in current year (2007)dollars. Thus, the impacts of possible future year inflation are assumed to impact costs andrevenues equally. To perform the analysis estimates of capital cost, life expectancy, operatingand maintenance costs, electrical power and parts and supplies were developed, as discussedin the sections that follow. The estimates, assumptions and resulting projected annualizedcosts are summarized in Table 1.

Capital CostsThe original cost estimates for all four alternatives were developed earlier this year and aredocumented in the previously cited March 2007 Preliminary Engineering report. Based on thelatest trends in the construction market, recent material price fluctuations, as well as thedegradation of the US dollar against other currencies, the March estimates were increased by15 percent. Given the uncertainties associated with these estimates, they are best used forcomparison among the options and not for budgeting purposes. Development of an actualbudget for a recommend alternative should be based on the latest available quotes in themarket once more is known regarding the actual timing of component procurement andinstallation.

Life ExpectancyIn order to convert the capital investment in each alternative to an annualized cost the lifeexpectancy of the investment must be estimated. In the event that Alternative 1 is chosen, theinterim repair is likely to make the tramway functional without further significant capitalinvestment for 7 years or less. This estimate of life expectancy for Alternative 1 is aprofessional judgment, given the age of the system and the uncertainties surrounding theuseful life of many of the existing tram’s components. Another way to look at thisassumption is that the investment in Alternative 1 might keep the system running for another7 years, at which time the system would be about where it is today in the sense of useful lifeexpectancy going forward. The work included in Alternative 1 simply addresses the knownissues with the current tramway. It makes minimal to no effort to address future, currentlyunknown maintenance issues. It is impossible to predict with any certainty what the nextfailure will be or when it might occur. Candidate components for potential failure include thegearbox, electric motor, carriage/hanger and bull wheels. Later, under the discussion of thecalculation of the revenue and cost per rider, the sensitivity of the results to this lifeexpectancy assumption for Alternative 1 is discussed. In the event that any of the systemreplacement alternatives are chosen, it is expected that the useful life of the system will be 30years or greater - 30 years is a fairly standard economic life span assumption for systems ofthis type.


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Discount RateIn addition to life expectancy an assumption regarding the time value of money oropportunity cost must be made to develop an annualized capital cost. In the public sector andgiven current market conditions 5 percent is a reasonable assumed discount rate and is typicalof the existing cost for public sector long term financing.

Operations and Maintenance (O&M) FeesThe estimates of O&M fees are based on the current contract for operations and maintenanceas performed by Doppelmayr. From an operations perspective, Alternatives 2 and 3 arefundamentally the same system as today, and while the new systems will likely require lesscorrective maintenance in the near term, no reduction was made for the maintenance fee(union labor, preference to keep “ahead” of maintenance rather than “behind,” and theredundancy creates some minor additional maintenance). Alternative 4 was increased for theanticipated staffing changes, as discussed with Armando Cordova (Operations Lead). Inaddition, Alternative 4 receives a credit for a reduction in the cabin attendant hours based onthe possibility of using only one cabin at a time for off-peak hours

Maintenance Parts and Supplies CostsThe recent historical parts and supplies expenditures were used as a baseline and expandedslightly based on the recommendations of Armando Cordova (Operations Lead). To adjustthis for Alternatives 2, 3 and 4, a relative estimate of near- to mid-term parts and suppliescosts was made. Parts and supplies costs for Alternative 4 are higher than Alternatives 2 and3 simply because it has more moving parts.

Electrical Power CostsThe recent historical power cost averages were used for Alternative 1 and as a baseline forestimating power costs for the other alternatives. Power costs for Alternatives 2 and 3 wereassumed to be nominally the same as Alternative 1. Power costs for Alternative 4 wereobtained by estimating the change in cabin hours under the dual system and applying thatratio to the current power usage. Additional adjustments were made to the Alternative 4estimates to account for its different power consumption characteristics compared to the otheralternatives. In summary Alternative 4 shows lower power costs compared to the otheralternatives since it can operate with only a single cabin during periods of low ridership. Inreality, the Alternative 4 savings may be greater because of the effect of peak power demandwhich should be smaller for Alternative 4. In addition, power cost estimates were increasedby an additional 15 percent to reflect a rate increase that is known to RIOC

Total Annual CostsTable 1 and Figure 1 illustrate the resulting estimated total annual cost for each of thealternatives. The annual cost is the sum of the annualized capital investment, annual operatingand maintenance cost, annual parts and supplies costs and annual electrical power costs. Ascan be seen annualized costs fall into a relatively tight range from $3.4 to $3.9 million. Thedifference between Alternative 2, which has the lowest cost and Alternative 4, which has thehighest cost, is only 15 percent. Despite having the lowest initial capital costs, Alternative 1is not the least expensive when its short life expectancy and greater on-going costs arefactored into the calculations.



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Table 1. Annualized Cost Estimates ($ 2007)

Tram Alternatives

1 2 3 4Capital Costs $5,600,000 $14,250,000 $17,250,000 $20,400,000Life Expectancy of Investment (years) 7 30 30 30Down Time for Replacement 8 weeks 6 months 7 months 7 monthsDiscount Rate 5.00% 5.00% 5.00% 5.00%Annualized Capital Cost $970,000 $930,000 $1,120,000 $1,330,000Annual Operating and Maintenance Costs $2,300,000 $2,300,000 $2,300,000 $2,400,000Annual Power Costs $140,000 $140,000 $140,000 $105,000Annual Parts and Supplies Costs $75,000 $25,000 $25,000 $35,000Total Annual Cost $3,480,000 $3,390,000 $3,590,000 $3,870,000

Figure 1. Annualized Cost Estimates ($ 2007)

Capital O & M Power Parts and Supplies

$3.9 M

$3.6 M

$3.4 M

$3.5 M

$4 M$0 $1 M $2 M $3 M

Alt 4: New Dual Shuttle

Alt 3: New Similar Tram + Redundancy

Alt 2: New Similar Tram

Alt 1: Replace Critical Subsystems



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4. RIDERSHIP AND REVENUE ESTIMATESRidership and fare revenue data for the tram were analyzed for the past three years. Figures 2and 3 illustrate the historic data and patterns for ridership and revenue by month of the yearfor each fiscal year. (The fiscal year for tramway operations runs from the start of the secondquarter in April through the end of the first quarter in March).

Figure 4 provides a more graphic look at month to month ridership changes for the last threefull years of operation. For the last full year of operation from September 2006 throughAugust 2007, the system carried 1.6 million riders and generated approximately $3.0 millionin fare revenue. In addition, ridership has shown a rough 20 percent increase month to monthover the past 2 years. Ridership growth reflects primarily the increased resident population onthe island, which with committed development is likely to increase by another 20 percent inthe next few years. As a result, the estimated baseline ridership and revenue for the analysisof costs and benefits was increased by 20 percent to a total of 1.9 million riders per year and$3.6 million in fare revenue.

For purposes of the benefit and cost analysis it was assumed that the basic system capacity,ridership and fare revenue would be the same for all four alternatives. This assumption isreasonable since from a capacity standpoint Alternatives 1, 2, and 3 are the same. Thisassumption may understate the ultimate capacity of the dual shuttle of Alternative 4, sincethis system’s greater flexibility should allow slightly shorter cycle times during periods ofheavy one-way passenger demand on the system. Ridership and revenue figures were thenadjusted to reflect the variable down time estimates for each of the alternatives, as discussedin the following section.

Figure 2. Ridership Trends by Fiscal Year

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Figure 3. Fare Revenue Trends by Fiscal Year

Figure 4. Ridership Trends by Month

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Sept. 06-Aug. 071.6 M Riders, $3.0 M Revenue

2004-2005 2005-2006 2006-2007

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5. DOWN TIME ESTIMATESEach of the alternatives will incur periods of down time both scheduled and unscheduled.Scheduled down time for maintenance can be planned to minimize user impacts, butunscheduled down time resulting primarily from mechanical failures cannot be planned andcould occur during periods of peak user demand. Table 2 summarizes the estimates for bothannual down time and the length of time that the system will need to be out of service toaccomplish the replacement.

The annual down time estimates are based on the experience over the past few years withAlternative 1 as the baseline. Estimates for Alternatives 2, 3 and 4 reflect assessments of thedegree to which down time will be reduced as a result of the newer components and thedegree of system redundancy provided by each alternative. Alternative 4 shows by far thelowest estimated down time, since the dual shuttle provides two separate and independentsystems, and the likelihood of system failures impacting both systems is very low. The downtime estimates were used to adjust the base estimated annual ridership and revenue for eachof the alternatives. Adjustments were based on a possible 7,436 annual hours of operation (20hours per day for 5 days per week and 21.5 hours per day for 2 days per week). Given theunpredictable nature of most of the down time occurrence the average ridership per hour wasused in the adjustment calculation.

The replacement downtimes are as indicated in the March 2007 Tramway ModernizationPreliminary Engineering report. With proper production, staging and financial incentives itshould be possible to reduce the replacement downtimes stated here. The duration of andrequirements for those reductions are under separate investigation.

Table 2. Estimates of Annual Down Time and Replacement Times

Tram Alternatives

1 2 3 4Annual Down Time 850 hours 580 hours 440 hours 25 hoursDown Time for Replacement 8 weeks 6 months 7 months 7 monthsAdjusted Annual Ridership 1.90 million 1.97 million 2.00 million 2.11 millionAdjusted Annual Revenue $3.60 million $3.73 million $3.80 million $4.00 million

Total possible annual hours of operation = 7,436 hours



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6. NET REVENUE AND COST PER RIDERBaseline Analysis

The measure of benefit cost calculated in the analysis is the net revenue or net cost per rider.Table 3 shows the results of this calculation for each of the tram alternatives. This analysisshows a small net positive revenue per rider and is reflective of the highly efficient tramoperation. While the analysis implies that the tram is profitable this is somewhat misleadingsince there are other management and administrative costs and expenses of the RooseveltIsland Operating Corporation (RIOC) and the Metropolitan Transportation Authority (MTA)that have not been included in the calculations. These costs are a necessary component of thetram’s operation but will be the same regardless of the alternative and therefore no attemptwas made to estimate them in the calculations.

The results shown illustrate the relatively small differences among the alternatives with only$0.11 per rider separating the alternatives. From this work one can conclude that on a purebenefit and cost basis, as a mover of people to and from the island, all of the tram options arehighly efficient investments. In addition, with relatively small differences in the resultsamong the alternatives the decision on which investment to make will be based on otherfactors.

Table 3. Net Revenue Per Rider

Tram Alternatives

1 2 3 4Total Annual Cost $3,480,000 $3,390,000 $3,590,000 $3,870,000Total Annual Revenue $3,600,000 $3,730,000 $3,800,000 $4,000,000Net Annual Revenue $120,000 $340,000 $210,000 $130,000Annual Ridership 1,900,000 1,970,000 2,000,000 2,110,000Revenue Per Rider $0.06 $0.17 $0.11 $0.06

Sensitivity AnalysisThe net revenue and cost per rider calculations are based on a number of factors as describedin the earlier sections of this report. Some of these factors involve estimates or forecasts thatare subject to varying levels of uncertainty and thus potentially differing outcomes. The twofactors having the greatest potential variability are the life expectancy estimates and theforecasts of potential future down time for each of the alternatives. To understand theimpacts on the resulting net revenue/cost calculations a sensitivity analysis was undertakenfor both factors.

Life Expectancy SensitivityThe base assumption is that the rehabilitation option (Alternative 1) would provide 7 years ofuseful life before more major work would have to be undertaken. However, it wasacknowledged that given the system’s age this a professional judgment and could in realityprove too short or too long. As a result, the impact of varying the life expectancy from 5 to 10years was tested. The other three alternatives are essentially new systems and there is noreason to expect any significant variability in their respective life expectancies. In addition,the 30 year assumption, while somewhat arbitrary, is an industry standard and of such lengththat varying it up or down by 5 years will have very little impact on the results of theanalysis.


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Down Time EstimatesWhile the hours of future system down time were forecast for each alternative based onhistorical information and other industry experience, the past is not a perfect predictor of thefuture. Therefore, it was determined desirable to understand how variation in these forecastsmight impact the results of the benefit cost calculations.

The baseline of 850 hours of annual down time for Alternative 1 was based on the entire dataset of maintenance and service records dating back to 2001. To approximate a reasonablelower bound on the Alternative 1 downtime, events such as weather, security events andregional power outages were removed from the data set. In addition, 2004 was removed fromthe data set as it was recognized as not having maintenance data and 2007 was removedbecause it was a partial year. The long outage related to cutting the rope too short in late2001 was also removed since this was judged to be an unlikely event in the future. Aftermodifying the data set as described above, the historic average annual down time forAlternative 1 was found to be approximately 600 hours.

To assess the impact of this change on the evaluation of Alternatives 2 and 3, the forecastdown time hours for both Alternatives 2 and 3 were revised to reflect the same percentage ofdown time forecast for Alternative 1 in the baseline data. Specifically, the baselineAlternative 2 downtime was 580 hours, or 68 percent of Alternative 1. In the sensitivity test,Alternative 2 was forecast to experience 410 hours of down time per year, nominally 68% ofAlternative 1 downtime. Likewise Alternative 3 was forecast to experience 310 hours ofdowntime. The down time forecast for Alternative 4 was left unchanged at 25 hours per year.

Analysis ResultsTable 4 shows the results of the sensitivity analysis when both the life expectancy and downtime estimates are varied as discussed in the previous sections. As can be seen the sensitivityanalysis has the largest potential impact on the forecast for Alternative 1, with a range on thehigh side of $0.24 per rider revenue and on the low side of -$0.11 per rider loss, a total rangeof $0.35. This is reflective of the higher degree of uncertainty over both the life expectancyand reliability of the rehabilitation alternative as compared to the replacement alternatives.Alternatives 2 and 3 show a minor variation and Alternative 4 is unchanged. In total, theresults of the sensitivity analysis do not change the general findings of the analysis other thanto highlight the uncertainties associated with the continued operation of Alternative 1 evenafter the proposed rehabilitation.

Table 4. Net Revenue Per Rider Sensitivity Analysis

Tram Alternatives

Revenue or Cost per Rider 1 2 3 4Baseline $0.06 $0.17 $0.11 $0.06High Range $0.24 $ 0.21 $0.13 $0.06Low Range ($0.11) $0.17 $0.11 $0.06



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7. NON-QUANTIFIABLE FACTORSAs discussed in the previous sections, it is apparent that considerations other than the cost tomove people will be the influencing factors in the choice of which tramway alternative toimplement. The other factors identified in the analysis include the means of rescue in theevent of system failure, system reliability and dependability, passenger service flexibility andADA access (access for the mobility impaired).

Safety / RescueAll of the alternatives meet the industry standards for passenger safety. The primarydifference from a safety perspective is not in the normal operation of the system, but rather inhow the failure modes are handled. In Alternatives 1 and 2, there would be no significantchange in the level of redundancy in the system. Those failures today that would result in arescue scenario would also drive a rescue scenario in Alternatives 1 and 2. Alternative 3provides an additional level of redundancy by designing for and supplying certain “live”redundant components. For example, the design of the system could be such that in the eventof a gearbox failure, within a matter of minutes, a second gearbox could be engaged and usedto return the cabins to the terminals. While this redundancy does not inherently change thesafety of the system under normal conditions, it dramatically changes the passengerexperience in a failure mode. Alternative 4 would take this concept one step further byproviding a means, under nearly any failure, of returning the cabins to the terminals. Forexample, it is possible with systems similar to Alternative 4 to return cabins to the terminalseven in the event of haul rope sheave failure.

Reliability/DependabilityThe tramway has become the island’s lifeline to Manhattan and a highly reliable anddependable system has great benefits to island residents. The benefit cost analysis includesconsideration of the lost ridership and revenue that results when the system is down both forscheduled maintenance and unscheduled failures but does not account for the non-quantifiable benefits of having a highly reliable service. From this perspective Alternative 4clearly performs the best since it practically eliminates both scheduled and unscheduled downtime. Alternative 1 is the worst with past experience indicating that an average of 850 hoursof down time will be experienced each year. While the newer components and addedredundancy of Alternatives 2 and 3 show some improvement over Alternative 1 they areforecast to experience 580 and 440 hours of down time per year, respectively.

Passenger Service FlexibilityFor purposes of this analysis, each of the Alternatives was judged to have the same passengercapacity. In general, the four Alternatives will have roughly the same effective cabin capacityand the same travel time from one station to the other. A major advantage of Alternative 4over the other Alternatives is not a change in system capacity, nor in headways but thatduring times of maintenance, the system can provide 50 percent capacity. Currently, when amaintenance procedure requires that the system be out of service there is no tramway servicefor that period, or the maintenance cannot be performed continually. In the case of a dualshuttle system, the maintenance could be performed during low demand times, much liketoday, with adequate, continuous service provided by the other cabin. In addition, the dualshuttle of Alternative 4 provides greater flexibility and should allow slightly shorter cycletimes during periods of heavy one-way passenger demand on the system. This in turn shouldallow Alternative 4 to carry slightly more people in one direction when peak passengerdemands warrant.


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ADA AccessAlternative 4 presents a major advantage for the Island’s mobility impaired population in thatit provides for the highest level of availability. This is achieved not by a different geometry ofcabins and terminals, but rather by virtue of the fact that maintenance can generally beperformed on one cabin while the other cabin operates. This would greatly reduce theinconvenience to those with special accessibility needs who generally find the subway to bean inferior mode of transit.



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8. CONCLUSIONSThe analysis of benefits and costs for the tramway alternatives demonstrates that within therange of the options being considered all would produce highly efficient investments to movepeople to and from the island, and that the differences among the alternatives are relativelysmall. Thus, the primary considerations in choosing an alternative become the morenon-quantifiable benefits.

Alternative 1 provides the baseline for comparison as it is the Alternative which is closest to a“do nothing” approach. However, as described previously and in the referenced March 2007Preliminary Engineering report, Alternative 1 does not provide the desired 25 years ofreliable service between Roosevelt Island and Manhattan.

In summary, using Alternative 1 as the baseline for comparison, the trade-offs become asfollows:

Alternative 2 – Replace with Similar TramwayThis alternative performs the best on a purely revenue per rider basis compared to all of theothers. In addition compared to Alternative 1 it:

· Reduces the likelihood of a system failure;

· Improves reliability and dependability by reducing unscheduled down time;

· Provides no additional flexibility improvement compared to Alternative 1 to respondto rescues should a system failure occur, work-arounds during scheduled andunscheduled outages, and peak passenger directional flow demands; and

· Has enhanced ADA access owing to the improved reliability.

Alternative 3 – Replace with Similar Tramway, Add RedundancyThis alternative reduces the per passenger revenue by 6 cents compared to Alternative 2. Inaddition compared to Alternative 2 it:

· Further reduces the likelihood of a system failure and the need for system rescue;· Further improves reliability and dependability by reducing unscheduled down time;· Provides no service flexibility enhancement over Alternatives 1 and 2; and· Has enhanced ADA access over both Alternatives 1 and 2 owing to improved

reliability.

Alternative 4 – Replace with Dual Shuttle OperationThis alternative reduces the per passenger revenue by 11 cents compared to Alternative 2. Inaddition compared to Alternative 2 it:

· Virtually eliminates the need for a system rescue operation should the system fail;· Further improves reliability and dependability by nearly eliminating unscheduled

down time;· Provides significant flexibility improvement compared to Alternatives 1, 2 and 3 to

respond to rescues should a system failure occur, work-arounds during scheduled andunscheduled outages, and peak passenger directional flow demands; and

· Provides the most reliable and dependable ADA access of all of the alternatives.

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