Search for track under build version 4.6 - not all PBR assets use PBR in the title, in fact it's usually only ground textures that do.
<kuid2:132952:157664:2> SAM Trk - III/B v17ru
<kuid:480583:100384> EM TRS19 SAP Track U.S. 132LB SG, FB, TP with Spikes, Shiny
<kuid:132952:158264> SAM Trk - Wood Ruined v2
<kuid:480583:100280> EM TRS19 SAP Track U.S. 132LB Med grey, FB, TP with Spikes, Rust
<kuid:124060:38241> NG42 60lb weathered, milled, no ballast
<kuid:480583:100281> EM TRS19 SAP Track U.S. 132LB Med Grey, FB, TP with Spikes, Shin
<kuid2:132952:157164:3> SAM Trk - III/B v12r
<kuid2:480583:100396:1> EM TRS19 SAP Track U.S. 132LB SG, FB, TP with Spikes, Rusty
<kuid2:368725:49050:1> Protrack NSWGR clean brown stone, new timber, baseplated
<kuid:124060:38242> NG42 60lb brown weathered milled 14p30
<kuid2:368725:49031:1> Protrack NSWGR ashes, mid-life timber, directly spiked
<kuid2:368725:49046:1> Protrack NSWGR clean brown stone, mid-life timber, baseplated
<kuid2:132952:157955:6> SAM Trk - PBS-1 v5
<kuid2:368725:49091:1> Protrack NSWGR clean grey stone, new timber, baseplated
<kuid2:368725:49041:1> Protrack NSWGR dirty brown stone, mid-life timber, baseplated
<kuid2:368725:49038:1> Protrack NSWGR dirty brown stone, mid-life timber, directly spiked
<kuid:132952:157064> SAM Trk - I/B v1
<kuid2:368725:49032:1> Protrack NSWGR dirty brown stone, old timber, directly spiked
<kuid:132952:158655> SAM Trk - B70 In Construction
<kuid2:132952:157855:9> SAM Trk - B70 v1aru
<kuid2:132952:155955:2> SAM Trk - Bl-3 v5ru
<kuid2:132952:157755:7> SAM Trk - Concrete Flat v1
<kuid2:132952:156964:1> SAM Trk - III/B v15ru
<kuid:132952:158564> SAM Trk - II/B r Snow
<kuid:132952:300004> SAM Trk - FFB 1t RUSTY
<kuid2:132952:158055:6> SAM Trk - PS-94 v2a
<kuid:132952:300007> SAM Trk - FFB 2t 4.7m RUSTY
<kuid2:132952:156864:2> SAM Trk - III/B v14ru
<kuid:132952:158464> SAM Trk - II/B Snow
<kuid:124060:38236> SG 60lb brown dirt weathered milled 14p30
<kuid2:132952:156764:2> SAM Trk - III/B v14r
<kuid2:132952:157364:2> SAM Trk - III/B v16r
<kuid2:132952:157464:2> SAM Trk - III/B v16ru
<kuid2:132952:157564:2> SAM Trk - III/B v17
<kuid:132952:158755> SAM Trk - INBK-7 Snow
Here, have a crack at these just to get you started.
Elstoko 4.6 PBR track with matching ballast (PROTRACK NSWGR Dirty brown stone, old timber, baseplated)