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    <title>Transport Research International Documentation (TRID)</title>
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    <copyright>Copyright © 2026. National Academy of Sciences. All rights reserved.</copyright>
    <docs>http://blogs.law.harvard.edu/tech/rss</docs>
    <managingEditor>tris-trb@nas.edu (Bill McLeod)</managingEditor>
    <webMaster>tris-trb@nas.edu (Bill McLeod)</webMaster>
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      <title>Transport Research International Documentation (TRID)</title>
      <url>https://trid.trb.org/Images/PageHeader-wTitle.jpg</url>
      <link>https://trid.trb.org/</link>
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    <item>
      <title>COMPOSITION BRAKE BLOCKS--INTERACTION BETWEEN COMPOSITION BRAKE BLOCKS AND WHEELS</title>
      <link>https://trid.trb.org/View/7672</link>
      <description><![CDATA[The service tests with various makes of K-block on the Berliner S-Bahn are described.  The object of the tests was to study the interaction of the two friction elements, block/wheel.  Although a strong tendency for the formation of cracks in wheel tires had occasionally been observed with K-blocks, in the service tests such a tendency could not be detected.  All the stages of grooving and follow-wear were present on the tires.  Similar phenomena had been observed by the SNCF on suburban services.  Experience gained by the DB showed that some difficulty arose due to metallic particles sometimes becoming embedded in the braking surface of the block.  K-blocks were used extensively on the London Transport Underground lines.  Thermal cracking, tire spalling and wear constituted a special problem on the frequently-stopping motor coaches with heavily-loaded small diameter wheels, running in tube tunnels.  The performance of a K-block depended on various parameters: characteristics of the block and of the wheel steel, application conditions, service conditions, weather, and shape of block.  The development of a universal K-block would be difficult.]]></description>
      <pubDate>Sun, 04 Dec 1994 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/7672</guid>
    </item>
    <item>
      <title>BRAKE-SHOES MADE FROM SYNTHETIC MATERIALS--REPORT OF ENQUIRY</title>
      <link>https://trid.trb.org/View/7670</link>
      <description><![CDATA[An enquiry was made to member organizations to gather information on the interest in and experience with the use of non-metallic brake blocks for railway brakes. Information was also sought from the literature on this subject.  The interest in non-metallic brake blocks is very great, and it seems that there introduction may result in economical advantages, no steps of any importance have so far been taken for the drawing-up, on an international level, of specifications for these brake blocks.  Only a few organizations have gained sufficient experience of many years standing or have introduced these brake blocks on any appreciable scale.]]></description>
      <pubDate>Fri, 08 Jul 1994 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/7670</guid>
    </item>
    <item>
      <title>COMPOSITION BRAKE BLOCKS--COMPARATIVE TESTS ON THE TESTING PLANT</title>
      <link>https://trid.trb.org/View/7671</link>
      <description><![CDATA[This report contains the results of braking tests from speeds of up to 160 km/h to a stop, and continuous braking tests at about 60 km/h.  These were made employing 15 different existing types of composition brake blocks, on the brake block testing plant of the SNCF.  The various types of brake blocks investigated had coefficients of friction remarkably similar both in character and magnitude.  At the moment of coming to rest, the percentage increases in the instantaneous coefficient of friction is up to one tenth of that when braking is affected with cast iron blocks.]]></description>
      <pubDate>Fri, 08 Jul 1994 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/7671</guid>
    </item>
    <item>
      <title>COMPOSITION BRAKE BLOCKS. LIMITS OF ENERGY DISSIPATION DURING BRAKING WITH TYRED WHEELS</title>
      <link>https://trid.trb.org/View/15160</link>
      <description><![CDATA[A large number of continuous braking tests have been carried out, on the brake test plant of the Laboratory for Vehicle Technology of Delft Technical University, using tyred wheels with both cast iron and composition brake blocks.  These tests were commissioned by ORE B 64 and by the CFF.  It was hoped by this means to establish a relationship between braking power and the time during which the relevant braking power could be tolerated by the wheel without detriment.  The limit laid down was the so called loosening time according to Bodey's temperature criterion (Bibliography reference 1).  This limit is the instant at which the tyre begins to loosen on the wheel centre.  The loosening time is determined by continuous measurement of the temperatures in the vicinity of the shrink fit surfaces.  Knowledge of the relationship between loosening time and brake power, i.e. what may be described as the limit of braking power, permits the greatest possible braking of vehicles to be determined, with the wheels in question, in relation to the axle load and to the route to be run over.  The present report contains the most important part of the results of the tests carried out.  The three wheels tested, of 900 mm mean diameter with different shrinkage allowances and tyre thicknesses represented a new wheel with maximum shrinkage allowance; a half-worn wheel and a wheel of the smallest permissible tread diameter with minimum shrinkage allowance, that is to say the entire range occurring in practices.]]></description>
      <pubDate>Thu, 16 Sep 1976 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/15160</guid>
    </item>
    <item>
      <title>COMPOSITION BRAKE-BLOCKS. THE DETERMINATION OF CHEMICAL AND PHYSICAL PROPERTIES OF COMPOSITION BRAKE-BLOCKS AND THEIR EFFECT ON THERMAL CRACKING OF TYRES</title>
      <link>https://trid.trb.org/View/15161</link>
      <description><![CDATA[The determination of the chemical and physical properties of various composition brake blocks, the measurement of maximum surface temperatures on tyres and the possible damage to tyres caused by various composition brake blocks are dealt with in the report.  Investigations which have been made enable the following conclusions to be drawn: Improvement of the braking performance on wet rails requires a content of hard materials of not less than 5%. The material selected shall be harder than the tyre steel (based on Moh's hardness scale).  There is no obvious correlation between chemical composition and modulus of elasticity.  Brake blocks with a high modulus of elasticity produce high local temperatures and thermal damage.  The modulus of elasticity should not therefore exceed 100 daN/mm to the 2nd power.  Maximum surface temperatures (hot spots) are influenced principally by peripheral speed at the beginning of braking.  The value of axle load also has a pronounced effect, whereas variation in brake block load has in general only a minor effect on the values of the surface temperature.  Maximum surface temperatures should not exceed 600 degrees C in order to avoid thermal cracking.]]></description>
      <pubDate>Thu, 16 Sep 1976 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/15161</guid>
    </item>
    <item>
      <title>COMPOSITION BRAKE-BLOCKS</title>
      <link>https://trid.trb.org/View/15162</link>
      <description><![CDATA[This final report serves to strike a balance after eight years of work, also showing the progress of the various subsidiary problems at the beginning of 1972.  In addition to a brief summary of the work done previously a somewhat more detailed account is given of some new studies (comparative tests on the brake dynamometer, effect of composition brake-blocks on the coefficient of adhesion, chemical and physical changes in the friction surfaces of composition brake-blocks and wheels).  The positive side of the balance-sheet contains numerous data and findings on the brake-blocks, permitting their use - though still limited for the time being - to obtain benefits regarding economy and braking technique, and as a result of great importance, a proposal for a provisional specification for type acceptance of composition brake-blocks, corresponding to the present state of development.  The negative side of the balance-sheet includes the shortcomings and drawbacks still affecting composition brake-blocks; these need to be taken into account as they restrict their application and economic advantages.  Those of major importance among the still unsolved problems are the questions connected with the coefficient of adhesion between wheel and rail, metallic inclusions and the effect on the braking efficiency of weather conditions, particularly in the winter.  The experts of the railways in the braking field will have to decide, with the aid of the data and findings available, on a given application of composition brake-blocks.]]></description>
      <pubDate>Thu, 16 Sep 1976 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/15162</guid>
    </item>
    <item>
      <title>COMPOSITION BRAKE-BLOCKS-EFFECTS ON ADHESION</title>
      <link>https://trid.trb.org/View/7673</link>
      <description><![CDATA[The effects of composition brake blocks on adhesion were investigated by the DB.  The measurements were analyzed statistically and the results plotted in the form of curves. Generally, lower adhesion values were ascertained when braking with K blocks than when using cast-iron blocks.  As such an effect is only acceptable if it is small, severe testing is, in this respect, considered to be necessary when submitting K blocks to acceptance tests.]]></description>
      <pubDate>Thu, 22 Jan 1976 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/7673</guid>
    </item>
    <item>
      <title>COMPOSITION BRAKE-BLOCKS-EFFECTS OF HUMIDITY ON BRAKING</title>
      <link>https://trid.trb.org/View/7674</link>
      <description><![CDATA[Tests carried out by the SNCF, to determine the effects of humidity on braking; were made with 20 different types of existing composition brake-block.  On the test rig at Vitry, braking tests were made from speeds of up to 160 km/h to a stop, and continuous braking tests were made with single cars at about 60 km/h.  In service, fly-shunting tests at speeds of up to 140 km/h were made.  The brake-block wear was not measured during the tests on wet rails.  The similarity of the curves obtained with the different makes of block on dry wheels was not repeated on wet wheels.  It would seem that not all the blocks have been designed and manufactured with the same object of obtaining satisfactory performances under wet conditions.]]></description>
      <pubDate>Thu, 22 Jan 1976 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/7674</guid>
    </item>
    <item>
      <title>COMPOSITION BRAKE BLOCKS-METALLIC INCLUSIONS IN THE COMPOSITION BRAKE BLOCKS</title>
      <link>https://trid.trb.org/View/7675</link>
      <description><![CDATA[Metallic inclusions is given types of composition brake blocks lead to excessively severe wear of the tires and of the blocks.  Recent experience has shown that not all composition brake blocks are affected by metallic inclusions.  A list indicates those composition brake blocks which, according to data collected up to mid-1969, are unaffected or are affected only in certain isolated instances by metallic inclusions, and which therefore behave favourably with respect to undue wear of the wheel-tire. The list also shows which organizations obtained these favorable results, with which type of vehicles and in which kind of service.]]></description>
      <pubDate>Thu, 22 Jan 1976 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/7675</guid>
    </item>
    <item>
      <title>COMPOSITION BRAKE-BLOCKS. EFFECTS OF ICE AND SNOW</title>
      <link>https://trid.trb.org/View/7676</link>
      <description><![CDATA[The effect of winter conditions on the braking distance proved to be considerable.  Using the results of all the tests undertaken in winter with composition brake-shoes it was calculated that the braking distances in winter were on average 36% longer than in summer.  The great amount of humidity due to the melting of the snow and the ice probably contributed considerably to the increase in the braking distances.  With one type of composition brake-shoes, the braking distances were, on the whole, shorter in the winter tests than in the summer tests.  This might have been due to the effect of the temperature on the coefficient of friction with these types of brake-shoes. The braking distances obtained with the low-friction brake-shoes were in certain instances more than 100% longer than those obtained during the summer tests, because of the effect of the snow and ice adhering to the blocks.  Since only a small number of preliminary-braking tests were carried out it is not possible to deduce from the results any valid conclusions concerning the effect of preliminary braking.]]></description>
      <pubDate>Thu, 22 Jan 1976 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/7676</guid>
    </item>
    <item>
      <title>COMPOSITION BRAKE-BLOCKS-TESTS WITH COMPOSITION BRAKE-BLOCKS OF VARIOUS DIMENSIONS AND SHAPE</title>
      <link>https://trid.trb.org/View/7677</link>
      <description><![CDATA[The German State Railway conducted the necessary tests on the bench and on the Berlin S-Bahn.  The tests were based on the assumption that the wheel wear might be diminished if the shape of the composition brake blocks was altered from the usual rectangular shape taken over from cast-iron blocks.  A number of different geometrical shapes of the friction surface of composition brake blocks were considered.  The coefficient of friction under various conditions was similar with all block shapes tested.  None of the block shapes tested produced any bad side effects. It was not possible to find any significant differences between the different block shapes when braking with one block per wheel or with two blocks per wheel; though tire wear for braking with one block per wheel was slightly lower than that for braking with two blocks per wheel.  The tests have not revealed any compelling reason for diverging from the customary simple rectangular shape brake blocks.]]></description>
      <pubDate>Thu, 22 Jan 1976 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/7677</guid>
    </item>
    <item>
      <title>COMPOSITION BRAKE BLOCKS</title>
      <link>https://trid.trb.org/View/13839</link>
      <description><![CDATA[The research question is a determination of the limits of brake heeating applied to wheelsets with shrunk on tires. The limits were determined by measuring the time of constant braking before the tire loosened on the wheel.  As a result, the shrinkage allowance for shrunk on wheels should be placed at a high value and brake blocks used with such wheels should be selected for good thermal conductivity.]]></description>
      <pubDate>Mon, 05 Jan 1976 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/13839</guid>
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